Why don't you do what I did and go to a "Flyer Exhibition" and speak to the schools themselves and compare each of their study material, you'll always get people recommending one school it seems - Bristol. I also visited the colleges and I narrowed my choice down to either between Oxford or Bristol. I eventually went with Bristol. Bristol's material was well presented, in colour, rather than in cheap looking black and white newspaper like text and simple diagrams - but each to their own.
I find that "visual" diagrams help me learn rather than just reading plain text. Bristol gives you 3D detailed animations for topics and a massive Question Bank; they managed to find a balance for me and ticked all my boxes.
Also worth noting that the course structure for each is slightly different. Bristol only provide distance learning, whilst CATS/OAA/London Met. provide full time courses as well.
So, over to you.. go and see these colleges personally and decide from there....