Sunday 9 October 2016 10.05am
Try SDV Jewelers at !00 Lower Marsh
, next to Boots the chemist. Most of their work is done within a day or two, sometimes whilst you wait.
If it is corrosion as you suspect and is a quartz battery driven mechanism then it might not be repairable and may require new works which are relatively cheap.
They will give you a quote free of charge.
I am an extremely satisfied customer and have used them for everything from pocket watches to a long case clock, batteries and watch straps etc.
Try them, it will cost you nothing for a quote.