I had rear foglight issues a while back. The light was flickering on and off. I’ve never actually used the rear fog as never been in need. Checked the whole system and I narrowed it down to the pcb unit behind the dash. The circuit board was loose inside so I glued it back. Worked ok for a while. As a pre MOT check it was failing again. Tried getting a replacement. Rutters didn’t have any, asked for photos.....factory part. Nothing coming so phoned the factory. Plenty in stock. Well not really as stock was for 1997 Plus8’s or earlier only. Mine’s a 2002. Can I have one and sort the wiring? No. Really? GRRRR.
Right then, Carbuildersolutions and a couple of others tried as they supply to kitcar builders. Before ordering ( about £30 max if I remember) one last look. Spotted a couple of iffy solder joints. Re-soldered them and ok ever since.
Still never used in anger but pre MOT checks only.