Their offers may have changed but despite Nottingham listing AAA-AAB as their typical offers I saw only AAB offers and I'm going there for maths in less than a week now. I was offered ABB/AAC because I was selfstudying a full FM A level but I expect you'll probably be offered AAB.
This is going to depend on what you want out of a university and your tactic(for example you may apply for 3 higher unis and 2 lower ones).
I would thoroughly recommend Nottingham and Manchester to start with. Bear in mind though they're very different universities. Manchester is very much a city uni whereas Nottingham isn't so much. Nottingham is on a campus with nothing but uni buildings, then surrounded by a residential area. The city being a short bus ride away. Birmingham, Sheffield and York are all very good maths unis and worth an application. Leeds seems to be a nice back up uni from what I recall of their 2011 offer. It has a decent rep too.
The rest weren't for me personally but thats your choice. You may want to consider Exeter, Southampton, East Anglia, Leicester, Loughborough, Royal Holloway, Surrey and Sussex. My personal favourites being Exeter and Southampton from that list