I asked the CAA where I can find a TMG Examiner in SE England. The reply I received is below. I think they mean 'do not'! What's the point of having examiners if they are a secret - they don't seem to have a problem listing AMEs?
Thank you for your email received.
Due to the UK Data Protection Act unfortunately we do hold a list of authorised examiners. You will need to contact Training Providers directly to see if they have authorised examiners you can use.
I am sorry that I could not have been of more assistance to you.
Yours sincerely