Center rear seat belt seized up - resolution

[RenoHuskerDu]

At some point after we bought the car and tested all the belts, and today when we have the French MOT scheduled tomorrow, the center rear seat belt seized up in the retracted position. It was impossible to get the belt out in order to fasten in a human bean. That would mean MOT failure.

I saw a related thread on Bimmerfest where the poster posited that it happened because he lowered the rear seat back to transport a bulky item.  He recommended wrapping the belt around a headrest before lowing the seat back.

I didn't find any advice out here on it but simply proceeded logically.  I removed the lower seat cushion as much as possible with a rigid belt holding it rearward, hoovered out all the old petrified food bits down there, then unbolted the seat belt mount.  Lo and behold, taking the tension off the belt freed it up.  No parts needed, no money spent.

So the car is ready for MOT after all.  Life is good.