They're look pivots, I don't know when this happened but I noticed it now.
Basically what's happened is the front 2 screws on the heelpiece are held in fine, perfectly strong.
However the 2 screws on the heel piece just won't bite the ski, they just keep turning. It seems as though it's threaded somehow.
Is this a result of a bad mounting job? or just unlucky and my fault.