diff --git a/app/controllers/assessor_interface/assessment_sections_controller.rb b/app/controllers/assessor_interface/assessment_sections_controller.rb
index 2559fe7048..fb0ae89c3f 100644
--- a/app/controllers/assessor_interface/assessment_sections_controller.rb
+++ b/app/controllers/assessor_interface/assessment_sections_controller.rb
@@ -96,10 +96,7 @@ def notify_teacher
         return
       end
 
-      TeacherMailer
-        .with(teacher: application_form.teacher)
-        .initial_checks_passed
-        .deliver_later
+      TeacherMailer.with(application_form:).initial_checks_passed.deliver_later
     end
 
     def unassign_assessor
diff --git a/app/mailers/teacher_mailer.rb b/app/mailers/teacher_mailer.rb
index 08adcb1309..9186978628 100644
--- a/app/mailers/teacher_mailer.rb
+++ b/app/mailers/teacher_mailer.rb
@@ -4,9 +4,6 @@ class TeacherMailer < ApplicationMailer
   include RegionHelper
 
   before_action :set_application_form
-  before_action :set_further_information_request,
-                only: :further_information_reminder
-  before_action :set_further_information_requested, only: :application_declined
 
   helper :application_form, :region
 
@@ -76,6 +73,8 @@ def further_information_requested
   end
 
   def further_information_reminder
+    @further_information_request = params[:further_information_request]
+
     view_mail(
       GOVUK_NOTIFY_TEMPLATE_ID,
       to: teacher.email,
@@ -129,23 +128,13 @@ def references_requested
 
   private
 
-  def teacher
-    params[:teacher]
+  def application_form
+    params[:application_form]
   end
 
-  delegate :application_form, to: :teacher
-  delegate :assessment, :region, to: :application_form
+  delegate :assessment, :region, :teacher, to: :application_form
 
   def set_application_form
     @application_form = application_form
   end
-
-  def set_further_information_request
-    @further_information_request = params[:further_information_request]
-  end
-
-  def set_further_information_requested
-    @further_information_requested =
-      assessment.further_information_requests.any?
-  end
 end
diff --git a/app/models/application_form.rb b/app/models/application_form.rb
index 68a0ca956d..e89b7941c2 100644
--- a/app/models/application_form.rb
+++ b/app/models/application_form.rb
@@ -267,13 +267,13 @@ def send_reminder_email(name, number_of_reminders_sent)
     case name
     when "expiration"
       TeacherMailer
-        .with(teacher:, number_of_reminders_sent:)
+        .with(application_form: self, number_of_reminders_sent:)
         .application_not_submitted
         .deliver_later
     when "references"
       TeacherMailer
         .with(
-          teacher:,
+          application_form: self,
           number_of_reminders_sent:,
           reference_requests:
             reference_requests_not_yet_received_or_rejected.to_a,
diff --git a/app/models/further_information_request.rb b/app/models/further_information_request.rb
index 146980a5e9..3dda340c02 100644
--- a/app/models/further_information_request.rb
+++ b/app/models/further_information_request.rb
@@ -48,7 +48,7 @@ def should_send_reminder_email?(_name, number_of_reminders_sent)
 
   def send_reminder_email(_name, _number_of_reminders_sent)
     TeacherMailer
-      .with(teacher:, further_information_request: self)
+      .with(application_form:, further_information_request: self)
       .further_information_reminder
       .deliver_later
   end
@@ -63,7 +63,10 @@ def expires_after
   end
 
   def after_received(*)
-    TeacherMailer.with(teacher:).further_information_received.deliver_later
+    TeacherMailer
+      .with(application_form:)
+      .further_information_received
+      .deliver_later
   end
 
   def after_expired(user:)
diff --git a/app/models/professional_standing_request.rb b/app/models/professional_standing_request.rb
index 641263ee04..3886a1e9d1 100644
--- a/app/models/professional_standing_request.rb
+++ b/app/models/professional_standing_request.rb
@@ -40,7 +40,10 @@ def expires_after
 
   def after_received(*)
     if should_send_received_email?
-      TeacherMailer.with(teacher:).professional_standing_received.deliver_later
+      TeacherMailer
+        .with(application_form:)
+        .professional_standing_received
+        .deliver_later
     end
   end
 
diff --git a/app/services/award_qts.rb b/app/services/award_qts.rb
index 95d784a765..84228fe071 100644
--- a/app/services/award_qts.rb
+++ b/app/services/award_qts.rb
@@ -24,12 +24,15 @@ def call
     raise MissingTRN if trn.blank?
 
     ActiveRecord::Base.transaction do
-      teacher.update!(trn:, access_your_teaching_qualifications_url:)
+      application_form.teacher.update!(
+        trn:,
+        access_your_teaching_qualifications_url:,
+      )
       application_form.update!(awarded_at: Time.zone.now)
       ApplicationFormStatusUpdater.call(application_form:, user:)
     end
 
-    TeacherMailer.with(teacher:).application_awarded.deliver_later
+    TeacherMailer.with(application_form:).application_awarded.deliver_later
   end
 
   class InvalidState < StandardError
@@ -44,6 +47,4 @@ class MissingTRN < StandardError
               :user,
               :trn,
               :access_your_teaching_qualifications_url
-
-  delegate :teacher, to: :application_form
 end
diff --git a/app/services/create_further_information_request.rb b/app/services/create_further_information_request.rb
index 5c66f7ae2f..c0b9f6adca 100644
--- a/app/services/create_further_information_request.rb
+++ b/app/services/create_further_information_request.rb
@@ -29,7 +29,10 @@ def call
         requestable
       end
 
-    TeacherMailer.with(teacher:).further_information_requested.deliver_later
+    TeacherMailer
+      .with(application_form:)
+      .further_information_requested
+      .deliver_later
 
     further_information_request
   end
@@ -38,11 +41,5 @@ def call
 
   attr_reader :assessment, :user
 
-  def application_form
-    @application_form ||= assessment.application_form
-  end
-
-  def teacher
-    @teacher ||= application_form.teacher
-  end
+  delegate :application_form, to: :assessment
 end
diff --git a/app/services/decline_qts.rb b/app/services/decline_qts.rb
index c204029427..42be6517dd 100644
--- a/app/services/decline_qts.rb
+++ b/app/services/decline_qts.rb
@@ -16,11 +16,10 @@ def call
       ApplicationFormStatusUpdater.call(application_form:, user:)
     end
 
-    TeacherMailer.with(teacher:).application_declined.deliver_later
+    TeacherMailer.with(application_form:).application_declined.deliver_later
   end
 
   private
 
   attr_reader :application_form, :user
-  delegate :teacher, to: :application_form
 end
diff --git a/app/services/submit_application_form.rb b/app/services/submit_application_form.rb
index 077d966bb1..bfa0ff90a5 100644
--- a/app/services/submit_application_form.rb
+++ b/app/services/submit_application_form.rb
@@ -32,17 +32,11 @@ def call
       ApplicationFormStatusUpdater.call(application_form:, user:)
     end
 
-    TeacherMailer
-      .with(teacher: application_form.teacher)
-      .application_received
-      .deliver_later
+    TeacherMailer.with(application_form:).application_received.deliver_later
 
     if !application_form.requires_preliminary_check &&
          application_form.teaching_authority_provides_written_statement
-      TeacherMailer
-        .with(teacher: application_form.teacher)
-        .initial_checks_passed
-        .deliver_later
+      TeacherMailer.with(application_form:).initial_checks_passed.deliver_later
     end
 
     if region.teaching_authority_requires_submission_email
diff --git a/app/services/update_work_history_contact.rb b/app/services/update_work_history_contact.rb
index f61a9c8c17..9a4a721f58 100644
--- a/app/services/update_work_history_contact.rb
+++ b/app/services/update_work_history_contact.rb
@@ -28,7 +28,7 @@ def call
     if email.present? && (reference_request = work_history.reference_request)
       RefereeMailer.with(reference_request:).reference_requested.deliver_later
       TeacherMailer
-        .with(teacher:, reference_requests: [reference_request])
+        .with(application_form:, reference_requests: [reference_request])
         .references_requested
         .deliver_later
     end
@@ -39,7 +39,6 @@ def call
   attr_reader :work_history, :user, :name, :job, :email
 
   delegate :application_form, to: :work_history
-  delegate :teacher, to: :application_form
 
   def change_value(column_name, new_value)
     old_value = work_history.send(column_name)
diff --git a/app/services/verify_assessment.rb b/app/services/verify_assessment.rb
index a704961c04..c743540578 100644
--- a/app/services/verify_assessment.rb
+++ b/app/services/verify_assessment.rb
@@ -52,9 +52,7 @@ class AlreadyVerified < StandardError
               :work_histories
 
   delegate :application_form, to: :assessment
-  delegate :teacher,
-           :teaching_authority_provides_written_statement,
-           to: :application_form
+  delegate :teaching_authority_provides_written_statement, to: :application_form
 
   def create_professional_standing_request
     if professional_standing && !teaching_authority_provides_written_statement
@@ -84,7 +82,7 @@ def send_reference_request_emails(reference_requests)
     end
 
     TeacherMailer
-      .with(teacher:, reference_requests:)
+      .with(application_form:, reference_requests:)
       .references_requested
       .deliver_later
   end
diff --git a/app/views/assessor_interface/assessment_recommendation_award/preview.html.erb b/app/views/assessor_interface/assessment_recommendation_award/preview.html.erb
index bea969f699..c54674f18b 100644
--- a/app/views/assessor_interface/assessment_recommendation_award/preview.html.erb
+++ b/app/views/assessor_interface/assessment_recommendation_award/preview.html.erb
@@ -8,7 +8,7 @@
 <%= render(PreviewMailer::Component.new(
   mailer_class: TeacherMailer,
   name: :application_awarded,
-  teacher: @application_form.teacher,
+  application_form: @application_form,
 )) %>
 
 <div class="govuk-button-group">
diff --git a/app/views/assessor_interface/assessment_recommendation_decline/preview.html.erb b/app/views/assessor_interface/assessment_recommendation_decline/preview.html.erb
index 724e1ed329..4069d784d4 100644
--- a/app/views/assessor_interface/assessment_recommendation_decline/preview.html.erb
+++ b/app/views/assessor_interface/assessment_recommendation_decline/preview.html.erb
@@ -8,7 +8,7 @@
 <%= render(PreviewMailer::Component.new(
   mailer_class: TeacherMailer,
   name: :application_declined,
-  teacher: @application_form.teacher,
+  application_form: @application_form,
 )) %>
 
 <div class="govuk-button-group">
diff --git a/app/views/assessor_interface/assessment_recommendation_verify/preview_teacher.html.erb b/app/views/assessor_interface/assessment_recommendation_verify/preview_teacher.html.erb
index a79dffc3cb..f6039c7b62 100644
--- a/app/views/assessor_interface/assessment_recommendation_verify/preview_teacher.html.erb
+++ b/app/views/assessor_interface/assessment_recommendation_verify/preview_teacher.html.erb
@@ -10,7 +10,7 @@
 <%= render(PreviewMailer::Component.new(
   mailer_class: TeacherMailer,
   name: :references_requested,
-  teacher: @application_form.teacher,
+  application_form: @application_form,
   reference_requests: [OpenStruct.new(
     expires_at: Time.zone.now + 6.weeks,
   )],
diff --git a/app/views/assessor_interface/further_information_requests/new.html.erb b/app/views/assessor_interface/further_information_requests/new.html.erb
index 8b52ec2483..8635d0d79e 100644
--- a/app/views/assessor_interface/further_information_requests/new.html.erb
+++ b/app/views/assessor_interface/further_information_requests/new.html.erb
@@ -6,7 +6,7 @@
 <%= render(PreviewMailer::Component.new(
   mailer_class: TeacherMailer,
   name: :further_information_requested,
-  teacher: @application_form.teacher,
+  application_form: @application_form,
 )) %>
 
 <%= form_with model: [:assessor_interface, @application_form, @assessment, @further_information_request] do |f| %>
diff --git a/lib/tasks/application_forms.rake b/lib/tasks/application_forms.rake
index 2c0e2f8327..97a69adf49 100644
--- a/lib/tasks/application_forms.rake
+++ b/lib/tasks/application_forms.rake
@@ -29,7 +29,7 @@ namespace :application_forms do
       next unless teacher.application_form == application_form
 
       TeacherMailer
-        .with(teacher:)
+        .with(application_form:)
         .application_from_ineligible_country
         .deliver_now
     end
diff --git a/spec/lib/application_mailer_observer_spec.rb b/spec/lib/application_mailer_observer_spec.rb
index 047b8b8122..1eee999137 100644
--- a/spec/lib/application_mailer_observer_spec.rb
+++ b/spec/lib/application_mailer_observer_spec.rb
@@ -31,9 +31,7 @@
 
   context "with a teacher mailer" do
     let(:application_form) { create(:application_form) }
-    let(:message) do
-      TeacherMailer.with(teacher: application_form.teacher).application_received
-    end
+    let(:message) { TeacherMailer.with(application_form:).application_received }
 
     include_examples "observes mail"
   end
diff --git a/spec/lib/mailer_preview_spec.rb b/spec/lib/mailer_preview_spec.rb
index 9481f381e3..43744c554a 100644
--- a/spec/lib/mailer_preview_spec.rb
+++ b/spec/lib/mailer_preview_spec.rb
@@ -2,9 +2,10 @@
 
 RSpec.describe MailerPreview do
   let(:further_information_request) { create(:further_information_request) }
-  let(:teacher) do
-    further_information_request.assessment.application_form.teacher
+  let(:application_form) do
+    further_information_request.assessment.application_form
   end
+  let(:teacher) { application_form.teacher }
   let(:notify_key) { "notify-key" }
   let(:notify_client) do
     double(generate_template_preview: notify_template_preview)
@@ -27,7 +28,7 @@
     subject do
       described_class.with(
         TeacherMailer,
-        teacher:,
+        application_form:,
         further_information_request:,
       ).further_information_requested
     end
diff --git a/spec/mailers/teacher_mailer_spec.rb b/spec/mailers/teacher_mailer_spec.rb
index 627d74f650..dc8af699dc 100644
--- a/spec/mailers/teacher_mailer_spec.rb
+++ b/spec/mailers/teacher_mailer_spec.rb
@@ -20,7 +20,9 @@
   end
 
   describe "#application_awarded" do
-    subject(:mail) { described_class.with(teacher:).application_awarded }
+    subject(:mail) do
+      described_class.with(application_form:).application_awarded
+    end
 
     before do
       teacher.update!(
@@ -54,7 +56,9 @@
   end
 
   describe "#application_declined" do
-    subject(:mail) { described_class.with(teacher:).application_declined }
+    subject(:mail) do
+      described_class.with(application_form:).application_declined
+    end
 
     describe "#subject" do
       subject(:subject) { mail.subject }
@@ -81,7 +85,9 @@
 
   describe "#application_from_ineligible_country" do
     subject(:mail) do
-      described_class.with(teacher:).application_from_ineligible_country
+      described_class.with(
+        application_form:,
+      ).application_from_ineligible_country
     end
 
     describe "#subject" do
@@ -119,7 +125,7 @@
   describe "#application_not_submitted" do
     subject(:mail) do
       described_class.with(
-        teacher:,
+        application_form:,
         number_of_reminders_sent:,
       ).application_not_submitted
     end
@@ -199,7 +205,9 @@
   end
 
   describe "#application_received" do
-    subject(:mail) { described_class.with(teacher:).application_received }
+    subject(:mail) do
+      described_class.with(application_form:).application_received
+    end
 
     describe "#subject" do
       subject(:subject) { mail.subject }
@@ -250,7 +258,7 @@
 
   describe "#further_information_received" do
     subject(:mail) do
-      described_class.with(teacher:).further_information_received
+      described_class.with(application_form:).further_information_received
     end
 
     describe "#subject" do
@@ -282,7 +290,7 @@
   describe "#further_information_requested" do
     subject(:mail) do
       described_class.with(
-        teacher:,
+        application_form:,
         further_information_request:,
       ).further_information_requested
     end
@@ -325,7 +333,7 @@
   describe "#further_information_reminder" do
     subject(:mail) do
       described_class.with(
-        teacher:,
+        application_form:,
         further_information_request:,
       ).further_information_reminder
     end
@@ -373,7 +381,7 @@
 
   describe "#professional_standing_received" do
     subject(:mail) do
-      described_class.with(teacher:).professional_standing_received
+      described_class.with(application_form:).professional_standing_received
     end
 
     describe "#subject" do
@@ -428,7 +436,7 @@
     let(:number_of_reminders_sent) { nil }
     subject(:mail) do
       described_class.with(
-        teacher:,
+        application_form:,
         number_of_reminders_sent:,
         reference_requests: [reference_request],
       ).references_reminder
@@ -489,7 +497,7 @@
   describe "#references_requested" do
     subject(:mail) do
       described_class.with(
-        teacher:,
+        application_form:,
         reference_requests: [
           create(:reference_request, :requested, assessment:),
         ],
diff --git a/spec/services/award_qts_spec.rb b/spec/services/award_qts_spec.rb
index ccbdebddb1..96f89bcaea 100644
--- a/spec/services/award_qts_spec.rb
+++ b/spec/services/award_qts_spec.rb
@@ -47,7 +47,7 @@
       expect { call }.to have_enqueued_mail(
         TeacherMailer,
         :application_awarded,
-      ).with(params: { teacher: }, args: [])
+      ).with(params: { application_form: }, args: [])
     end
 
     it "changes the status" do
@@ -93,7 +93,7 @@
       expect { call }.to have_enqueued_mail(
         TeacherMailer,
         :application_awarded,
-      ).with(params: { teacher: }, args: [])
+      ).with(params: { application_form: }, args: [])
     end
 
     it "changes the status" do
diff --git a/spec/services/decline_qts_spec.rb b/spec/services/decline_qts_spec.rb
index dc9efae5e5..0263491de4 100644
--- a/spec/services/decline_qts_spec.rb
+++ b/spec/services/decline_qts_spec.rb
@@ -15,7 +15,7 @@
       expect { call }.to have_enqueued_mail(
         TeacherMailer,
         :application_declined,
-      ).with(params: { teacher: }, args: [])
+      ).with(params: { application_form: }, args: [])
     end
 
     it "changes the stage" do
diff --git a/spec/services/send_reminder_email_spec.rb b/spec/services/send_reminder_email_spec.rb
index ff9e9abecb..817c2f3633 100644
--- a/spec/services/send_reminder_email_spec.rb
+++ b/spec/services/send_reminder_email_spec.rb
@@ -33,7 +33,7 @@
           :further_information_reminder,
         ).with(
           params: {
-            teacher:,
+            application_form:,
             further_information_request: remindable,
           },
           args: [],
@@ -67,7 +67,7 @@
           :application_not_submitted,
         ).with(
           params: {
-            teacher: remindable.teacher,
+            application_form: remindable,
             number_of_reminders_sent: a_kind_of(Integer),
           },
           args: [],
@@ -84,7 +84,7 @@
           :references_reminder,
         ).with(
           params: {
-            teacher: remindable.teacher,
+            application_form: remindable,
             number_of_reminders_sent: a_kind_of(Integer),
             reference_requests: [reference_request],
           },
diff --git a/spec/services/submit_application_form_spec.rb b/spec/services/submit_application_form_spec.rb
index 5b67163257..dc7fdb0432 100644
--- a/spec/services/submit_application_form_spec.rb
+++ b/spec/services/submit_application_form_spec.rb
@@ -154,7 +154,7 @@
       expect { call }.to have_enqueued_mail(
         TeacherMailer,
         :application_received,
-      ).with(params: { teacher: application_form.teacher }, args: [])
+      ).with(params: { application_form: }, args: [])
     end
   end
 
@@ -191,7 +191,7 @@
         expect { call }.to have_enqueued_mail(
           TeacherMailer,
           :initial_checks_passed,
-        ).with(params: { teacher: application_form.teacher }, args: [])
+        ).with(params: { application_form: }, args: [])
       end
     end
   end