does anybody know if the mk4 golf rear caliper will fit the mk2 golf carriers?? i seem to remember reading somewhere that they fitted??

Yep they do, I have 3B Passat rears on my MK2 Golf using the original carriers. Better caliper (same as the MK4) aswell, Never get MK2 Golf ones to work properly.

suprisingly the mk4 calipers are cheaper too

ross, so you know if all mk4's have the same rear caliper?? or is it just the ones from a higher powered version that i need to get

The only ones that are different are the Anniversary and the V5/6 rear brakes which are vented. These calipers are wider to accomodate the thicker disc. So anything off anything else should be ideal. All you normally need to do it make a new brake pipe and figure out the cable for the handbrake (runs a different way).