bluw28

You may have sorted this by now but I had a similar issue on an 03 plate Fabia with a seatbelt not retracting. These cars suffer from a well documented issue (search this site) of water leaking in through the rear window/doors and pooling in the rear footwell. In my case this was causing the seatbelt and mechanism to get damp. I only realised this when I had removed the seatbelt as the carpet around the base of the unit was damp and mouldy. I pulled the seatbelt to its limit and carefully dried it with a hairdryer. I did then give it a spray of furniture polish like run4mo suggested above, replaced it and sorted the rear window leak. It worked perfectly for several years until we sold the vehicle. Given the recent weather, I would suggest investigating this before replacement.