[ollysb]

The rental market in London is pretty ferocious. I don't think comments could work because you'd always run the risk that somebody has decided they like a place and want out off other people from looking. In the end you'd still have to check the place yourself. I like a lot of your other ideas though and user photos could definitely work.

[edparry]

I agree with the user comments issue. Maybe a way of vetting them, possibly if other viewers agree with previous comments, they become publicly available?

EDIT: ...but even then, you might not get personal opinions. Tough one!