Windy Pants,
Plus, they're required to return a 6% profit to the exchequer.
AOPA have been trying hard for a few years now to get the CAA to tone their charging regime down, against heavy opposition from the airlines. Apparently to the point that the CAA set up a separate committee to review charges with just CAA staff and airline representatives on it.
Join AOPA, the more members, the more likely they are to be listened to.