Hi I'm trying to get the rear piston back into the calliper with no success at all can anybody help me with any advice please???

how are you trying to do it? you do know you have to wind them back in?

Hope this isn't too late for you...
Left piston winds in anti-clockwise, the right one clockwise.
You need to push them at the same time, and open the bleed nipple or disconnect the hose.

More info and pics here...