After extensive reading I realised that sending back to China was going to be a frustrating experience. Popped down to my local hardware store and purchased some liquid metal polish (like Brasso) for £1. 10 minutes of rubbing took the AR coating right off. I actually prefer it without the coating, obviously because with the peeling it looked horrific, but also, the overly blue tint has now gone. There is AR coating under the crystal, so there is still a slight tint at certain angles, but nothing like it was before.
Fingers crossed the watch stopping was due to a day of inactivity. If I notice it again I'd rather have it repaired locally than send it back.
I recommend taking the AR off Frost. Hope you resolve your situation.
Regards.