[classicchrisk]

In such a case Chris, a small piece of Blu tack is indeed the best option.
I generally only use tape when there is not enough of a recess for Blu-Tack to be effective

The only issue is that I expect the track will want it visible. There's no space for Blu Tac on the screw head. It would stick against the guide. 

Yes, I use Blue Tac inside the body post, but only I know it is there, unless the car is disassembled!!