After all, it costs thousands to obtain and keep up an examiner rating, the money has to come back from somewhere...
Quite right, but I don't charge for revalidations and
AFAIK none of the other local examiners do either.
Regarding asking the CAA for a dispensation ... I don't know of anyone who's done it but I suspect that if you worked for the queen and had spent a lot of time recently in hot sandy places you may find a sympathetic ear.
HFD