Rotary Watch - 3rd Party Repair Issues

[Gluggy]

Asking on behalf of my father in law so sorry for the lack of details.... He has a Rotary around 30years old that has been sat around for a bit, had the battery replaced and noticed it was rapidly losing time. Anyway to cut a long story short he took it a well known high street for repairs, they have had three goes at it and now given up.

I don't think the watch is worth huge amounts but does have quite a bit of sentimental value which complicates things a bit. I've looked on the Rotary website and see it can be sent to them directly - can anyone who has recently done this let me know the rough costs / time frames and quality of repair?

Failing that and bearing in mind its not an expensive watch can anyone recommend a decent repairer?