It's the screw voles,they are so big that the screw doesnt bed down onto the chassis,so the screws are tight but just moves in the hole,
They are sending me the original so I will just fit that as im sure it will be fine for club racing,
Yeah it was a bummer, but like you say I had a hint of just how amazing the car is going to be once sorted : )
Just re reading this, make sure your not using strange screws, i know associated had screws that were not fully threaded up to the countersunk area. so the screw could be bottoming out in the alloy part without tightening against the chassis. Worst case try some of the kit countersunk screws from another part of the car.