Add thread safety ( guard against collection has changed errors)

[OracPrime]

Upside: there won't be an error is something is logged whilst someone is enumerating the results of (e.g.) RecordedLogs.

Downside: it has to make a copy of the list. However it's only the list object that will be duplicated, the actual tuples in the list won't be.

[OracPrime]

I believe the above failures are a permissions issue related to the fact that I triggered the change, rather than horsdal.

[OracPrime]

The two commits are entirely independent, although I recommend you take both :)