It's been a long day, so excuse me if i am being stupid.

All i want to do is to mate the "Gimbel" assy to the plate. I want the screw to move in the slot and be constrained by the ends of the slot.

If i unsuppress the concentric mate on the gimbel pin the assy acts as i would expect, i.e. it rotates in the slot but is not constrained. If i suppress the concentric mate and unsuppress the slot mate it is constrained by the slot, but now the pin moves.....

Should you not be able to use concentric and slot mates?