Hi,
I am in the same position (except for aero/general) , and am not sure either. Here are the pros and cons that I have come up with:
Bristol: Pros: Better course than Durham. Nice if you like cities. (IMO)Better industry connections.
Cons: Big loud city. You make the assumption that you'll like the specialisation you've chosen. London-Bristol is First Great Western. Accommodation far from faculty buildings. Supposedly the worst prospects for earnings...?
Durham: Pros: Specialise mid course. Pretty. Collegiate system. On EC mainline - good access to the rest of the UK.
Cons: Apparently the worst if you believe the league tables. It'll never quite be Cambridge. Some colleges nicer than others. Nightlife (Not that I care).
Cambridge: Pros: You get so say you went to Cambridge. All incredibly pretty. Don't specialise immediately. Collegiate system.
Cons: Work depressingly hard. Spending a good portion of your life to reapply with a big chance of being rejected again - good idea, bad idea? Lets not make remarks about stereotypes...
Personally, I question whether it even matters that much what you/I choose. How well you do is likely to largely depend on how hard you work, not the university you go to. Where ever you go, you'll be goings somewhere many people can only dream of getting into, and be studying with the best. And everyone ends up loving their university.
Good luck anyway. Who knows, perhaps we will end up meeting each other at some point?
AnythingGoes