Spoke to the H Samuel CS that I guess do all the legwork for the Signet Group. Long wait on the phone but when they answered were exceedingly helpful and apologetic.
Asked me whether I would like a partial refund or if there was something else that they could do? I enquired as to the possibility of a new outer and the requisite tag. The very nice chap said that he will investigate and get back to me by Monday next week at the latest.
At no point did he mention returning the watch. I guess they don't want to go down that route.