'But the plain fact is that we are now such a minority the governement doesn't have that much to loose by letting us have the same tax concessions as the RFA.'
My understanding is that the RFA do pay tax when afloat; however, they have the ability to claim some of it back at a later date if they fulfill the qaulifying criteria/criterion (possibly more than 6-months away in the Financial Year). While that may seem like a good deal - have a look at their basic salary; they get paid significantly less than their RN counterparts for serving in the same bit of water with fewer defensive aids.