David,
Do you really think they could charge an £800 fee to an AME and then charge a lesser fee to a GP? FIEs recently discovered that to retain their existing privileges to train and test PPL (FE)s they have additional charges of £1377 for a Senior Examiner test, an ATO Approval Fee of £1659 and if they also want to provide the Revalidation Seminar, which is the same as the Examiner Course, another £1000. So to stand still an additional £4036! There are unlikely to be any takers.