I think it would be ridiculous for someone to neg a seller for updating a listing that they had placed a snipe for and won simply because they hadn't re-checked the listing at any stage and taken note of said updates.

I absolutely agree it would be ridiculous but you don't have to sell for too long to find out that some buyers are ridiculous in their expectations.

That was only one reason why many of us said editing listings was not a good idea, the main one was the item not being searchable for some of the time, the OP was absolutely certain that this was not the case so good luck to them!