Finally got around to sorting out my drivers seat belt which was very sluggish retracting.
I took the seat belt mechanism out to check if the plastic guide had come dislodged which fouls the belt when retracting, unfortunately the guide was in place. Sprayed a few bursts of silicon spray on the visible moving parts of the belt mechanism I could see before reinstalling it. I decided it must be dirty seat belts causing friction and slowing the belts retraction. So pulled the seat belt out as far as it would go and put a small clamp on the belt to stop it retracting. Then got half a bucket of hot water with some washing powder dissolved in it and put as much of the belt into the water as I could. Left submerged for 10 mins. then wiped belt off with micro fibre cloth, you should have seen the dirt that came off on the cloth and the colour of the water

. I didn't think the belts were that dirty to be honest. Gave the belts a rinse off in cold water and then another wipe and left extended to dry. Once dry I gave then a quick spray with silicon spray, the belts certainly retract a lot quicker now, plus the belts feel better as well, so well pleased with the result