ok this maybe a bit hard to explain- I was under my buggy and at the front nose cone on the drivers side, just above the front gearbox mount is a hex nut about 21mm, with a smooth round protruding end and an electrical wire coming out of the end of this that snakes back along the gearbox upto near the motor where it ends in a fuse.Its not the gearbox earth either.

Could this be a reverse light switch? I get no postive current from this when in reverse or anything else for that matter.Did beetles ever have one? My spare gearbox doesnt have this part at all.

yep - sounds like the reversing switch

should be 2 wires. One coming from power and the other going to reverse lights