Rear UPVC Door issue
Discussion
It's pretty fiddly to do. Have a watch of some youtube videos for how the gearbox works but if it's gone once then entirely possible that the mechanism itself is worn (ie the teeth are worn and caused what's happened) so every chance it could happen again. If you end up replacing the gearbox, make sure you get a straight match and also a genuine one as there's quite a few crap ones which are made of cheese out there and bend if you fart near them.
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