Well, that was more complicated than anticipated. Looks like the surveyor actually did some surveying (contrary to horror stories I've heard elsewhere) and picked up on some things that warranted a closer look, and so we had to send someone up to clamber around on the roof (with most buildings here being three or four storeys, it's more of a skill than it sounds). Turns out it's nothing too serious, although we will need to do a bit of work when moving in. As it happens, the scope for downward offering was limited by virtue of the next offer down being quite close to ours - so we ran the risk of the seller saying "Well, in that case we'll offer it to the next bidder"; turns out that things aren't quite as simplistic as you might first imagine.
I do wonder how much loaves of bread would cost if they were sold by blind auction, though.
Incidentally, I should probably mention that the place is on a Crescent in Morningside. But not, sadly, Morningside Crescent: you have to go to Aberdeen to find one of those.