Me Again! I have found another situation which is also troublesome. I suppose it's obvious really but if the indirect configuration can't connect, then the logging will fail, but therefore the failure to connect isn't itself logged. I'm now recommending my colleagues to use custom logging in tandem with logging to a text file. The custom logging is used for reporting, but if there is no info in the custom log, we start looking at the text file to troubleshoot.
Cheers,
Paul