I would recommend Swiss Watch Repairs on St Anne's arcade, sell and repair a variety of high end Swiss watches. I have used them for watch repairs, excellent workmanship donein about 2 weeks. The catch is it'll cost £400! As ever it's about balancing what the watch means on a personal level to whether it's sensible to repair it.
There is another watch booth type place on the first floor of the Arndale near the Market who don't do in house repairs but send to the manufacturer repair/service centre, so will cost just as much and take 6/8 weeks. Good luck!