The way to stop PAYD is simple. Everybody, and I mean EVERYBODY, on a unit should stop eating in the messes altogether. Also, don't use ANY of the on-base recreational facilities, bars, NAAFI, etc - go to the local pub or downtown instead.
The companies running this fiasco would then suffer massive losses and the scheme would have to be abandoned.
A cynic might think that the reason the core menus have been turned into absolute chod is to force you into paying more for edible food...more profit for the contractors, since they surely can't be making money from providing just the core menu...