It’s been a long time since I’ve been to Edinburgh and I’ve never been to York (or the North much) so for me in my limited knowledge it would have to be Bath.
I think it’s a shame that we only have pockets of beauty in the UK. I used to live in Switzerland and the question there would be more like, what part of Switzerland isn’t beautiful (and that would be quite a head scratcher and I wouldn’t know the answer). If every town and city there can be beautiful why do we have to be so ugly 😕