Hi Rich1,
I had a simular problem, i bought an f plate golf mk2 git 16v which working electric windows as the winter turned up they both stopped working.
I was checking all the cabling and the fuses for weeks with out finding the cause of tjhe problem.
So i decided to remove the motor from the door, remove the 5 screws to release the steel plate, put some greese and WD40 (you will see a small wheel with the wire wrapped round) then place the plate back in place.
Also theres another part to the device, there's two screws connecting the motor, remove these two screws and put some more WD40 in, out all back together and they shoudl work. They did for me.!
Good luck