Thanks for all the help ith resetting the rear brakes after a disc and pad change. I did go to Halfords for the piston tool but it did not list alfa as a make it was designed for and it was £20. I used a valve compression tool with an adjustable leaver. This sorted the pistons ok.
The front discs i could not fit as they supplied solid instead of vented. Still they will be ok for next weekend.
I brought a new Air mass flow unit off Ebay which has now failed, wasnt polar. Moral is to get the correct part and pay out.