You are wasting your time if you want to work in a City law firm. If you want to work in a high street firm in Nottingham, then Trent, if London, City - and try to get work experience with firms which might take you on whilst at university.
City firms don't accept less than AAB, they can make exceptions if you went somewhere good like Bristol or if you have a first...but they won't for these universities. You will be filtered out. A first from any of these universities will give you good opportunities both within and outside law -- but even with a first from City you will struggle to get a London law firm, especially given your A-levels. City is the best university of these and most well known - but honestly it is not a good university. I can't recommend you go there though - look on unistats, about 1-3% get firsts, 35% 2:2s. Trent has a higher number of firsts, 11%, but more 2:2s and 3rds, around 45%. Basically you have to be right at the top of the cohort in the year to even stand a shot at some firms which is far from guaranteed.
You are better off applying for a less competitive course elsewhere. Quite frankly a lot of employers will bin your CV from these universities. I've got a first from a Russell, and a load of work experience, and am currently working in a crap job I hate. I don't want to sound jaded, but the graduate recruitment market absolutely sucks. I'm starting to apply for training contracts now I think, having decided to leave it for a bit - I reckon I might get a few interviews, but most will reject me beforehand. It is simply that competitive.
In sum, it comes down to a) do you want to paralegal b) end up in a high street firm. If you are happy with these outcomes, then choose the university nearest the area you want to ultimately live and work.