My OWC Milsub has stopped hand winding, it's always felt a little clicky but now won't hand wind although there are turning sounds and it winds on the wrist. I don't think it's in need of a service as such so are there are any quick checks I ought to do before sending it off to someone? Is there any chance magnetising would make the spring stick enough not to wind as I suspect it may have been moved to sit on top of a tablet case with magnet closure?

I'd read that some watch repairers were reluctant to work on chinese movements - is this still the case? I haven't asked Duncan at Genesis yet but will do idc, thanks.