OK, if the charge was not part of the camo discussion, set up and contract, dont pay this unsolicited cost and find another camo who wont lift your leg! (I know, easier said than done, but we owners should do this to ensure camos who try it on are driven away.
Mine has dropped its annual check charge (a bit) and introduced the camo charge (an almost similar bit) so overall its only a little dearer, but I think they are covering a lot of new costs -they need 4 approvals now, when last year one did the same job!
This problem has only arisen because the CAA have jumped feet first into the Part M quagmire, to do what they think is EASAs bidding without any forward planning or risk assessment or thought of the consequences of what is mostly a hobby industry.