I may be a bit behind with this reply (I couldn't be bothered to read ALL of the other responses... but:
I got ABB at A-level (2011 leavers) and didn't get into my firm or insurance (SOAS- AAA, Bristol- AAB). I had to go through clearing and ended up at University of Westminster. Now, as silly as it sounds, it really depends how much you value prestige and reputation. At the time, I was mortified at the thought of attending a 'crap uni' having blown the 'I'm a top student who's too good to even consider anything but a top uni' trumpet, and dreaded going there. It turns out that I'm very happy here. Now since you said you're not all that interested in working for a big city firm, I don't suppose the opportunities available to us as students who are studying slap bang in the centre of the legal world would be a consideration... but if there's even the slightest chance you'd want to work in a city firm but aren't applying to a RG uni, I'd definitely recommend Westminster. In fact, I'd recommend it regardless, as you'll find that many people outside of London will be impressed if you say you study Law at 'the University of Westminster'. Sounds prestigious, you see? That's not to say that the legal practitioners outside the capital are stupid- far from it. But they're certainly less picky than city firms, whilst at the same time, you're background at a uni in the centre of all things law and politics is more likely to count for something.
ON THE OTHER HAND.... where's the harm in applying maybe to one RG uni? It really isn't all about the grades. Now, as it happens, I've been suffering from severe health problems whilst studying at uni. I already suffered from my condition prior to moving away, but it has worsened since. For that reason, I'm planning on moving back home permanently when I return this summer. I went down the UCAS route once more, this time applying for local universities that were, on paper, as good as or better than Westminster. I applied to University Of Birmingham, College Of Law Birmingham, and Staffordshire University (the latter merely because they offer a two year LLB). I had offers from all three- yes, Birmingham too. Despite my only having achieved ABB, they still saw fit to offer me a place, because at the end of the day, its not all about the grades. In addition to my personal statement, I also sent a letter direct to the LLB admissions tutor emphasising my extra-curricular activities, academic potential, and reasons for wanting to attend Birmingham. I doubt I would've got in had I not gone that extra mile. Don't assume that you'll get rejected so easily. Write to RG unis, ask them if they'll consider students who don't meet the entrance criteria. Or simply risk it with one or two options on your UCAS form and send a letter like I did, to be considered alongside your personal statement. There really is no harm in trying, it's worked for me twice (the first time was with SOAS). Its hard for them not to at least
consider someone who makes that little bit extra effort...
Now that was an essay and a half! :| If you're still awake... sorry! :P