Should respond with a 'cannotDisseminateFormat' for non-theses

[jesusbagpuss]

Currently an empty element is output:
<uketd_dc:uketddc xsi:schemaLocation="http://naca.central.cranfield.ac.uk/ethos-oai/2.0/ http://naca.central.cranfield.ac.uk/ethos-oai/2.0/uketd_dc.xsd" ></uketd_dc:uketddc>

From: http://www.openarchives.org/OAI/openarchivesprotocol.html#ProtocolMessages the correct response should be:
<error>cannotDisseminateFormat</error>.

[jesusbagpuss]

Looks like this is a deeper issue than can be resolved in this plugin.
Altering the output at the plugin level will still render a <metadata> element which would include the <error> response. The example on the OAI-PMH page above shows no <metadata> element.