Hi Jim,
I've no doubt that you're right about the timing of the actual photo. There was a little uncertainty about whether it was the lady widowed in 1892 or a later photo of one of her daughters. The lack of any earlier references to the address suggested that it might be one of the next generation but I'm now fairly sure that all the daughters died in childhood (and we should be able to get certs to prove that).
The only problem is how to find out whether this photographer can have been at the address on the card mount in 1892 or, if not, how we have a photo apparently taken in 1892-3 but on a mount with an address that did not exist until later.
If the photographer was at that address in 1893 and still there or family still there in 1911 then he or she should appear on the 1901 census at the same address and then we would have to seek out directories for the years just before that to try and find a mention of it for confirmation.
I can imagine all sorts of reasons why one would go back and ask the photographer to make another copy later but, if we are really talking about at least ten years later, it seems odd to reprint a mourning photo on a "mourning card" mount rather than on a standard mount.