New movement or repair for Omega Speedmaster 3220.50.00 replica

[Fatfingers]

I wore this everyday for a couple of years and regularly went swimming in it, which may well be the problem. Now it sometimes runs, sometimes doesn't and often just stops. I'm guessing a new Chinese movement for it is the easiest fix? I tried a local watchmaker but he won't fix replicas. Irritating, because he charged me a pretty penny to overhaul an old wall clock of mine, which know keeps worse time than it used to. Can anyone suggest either a UK based person who could service this, or a place I can buy a new movement for it? Thanks.