The LNAT is a required test by some universities. My choices didn't require it and so I didn't take it however my housemate did take it for one of his subjects. From what he's said and looking at the papers if you do Critical Thinking at A Level the LNAT would be a piece of piss... Having said that DO NOT do Critical Thinking A Level as one of your main three. I did it purely because it was required, not because I wanted to. (It also isn't acknowledged by a lot of universities as a full A Level but will be acknowledged as an extra AS.)
If you want to study an LLB then A Level law isn't required, also if you only look at Criminal Law it won't even tell you if you like Law really. (I know people who loved Criminal but then when we got to Contract, EU, Trusts and Land wanted to quit) It will give you a taste of how you have to learn things though.
I did A Level Law and I'm glad I did as I got an A in it but part of me wishes I had done English instead.
Don't do Textiles unless its a fourth A Level. If you do History then law schools will love you, similarly if you do English. Politics also seems to have gone down well (I did law, politics, history and as critical thinking and received 5 offers).
They also like sciences. I know a lot of people who did Physics and Maths along with History and got accepted to various places. Essentially though if you do traditional subjects (the sciences, maths, history, english, languages. Not textiles, business studies, sociology, media) then as long as you get decent grades any uni will accept you.