Hi Miles and Mike,
I discounted Dumfries, purely on the grounds that I could not find a smith with a 'W' initial, of course that's not to say that one did not exist as one may come to light yet.
I was wondering about the possibility of Peterhead, were William Smith and William S. Ferguson both worked there. William Smith was known to have used the 'fouled anchor' mark. But to me, I feel the 'W' is more likely, due to the placement of the marks, to be that of the surname, maybe.
I also wonder, I know nothing of the history of Peterhead with the exception that it is a small port, if it was ever host to a Royal Navy presence, as my thoughts regarding the other mark is that it strongly resembles a government broad arrow, just the sort of mark that would have been struck on mess silver. It would certainly appear that this mark was made by a different hand and I suspect that it was struck after it had left the shop of 'W'.