inb4 you shouldn't do Law if you want to do it at uni.
And it's kinda true, you know.
I also want to do Law at uni. I'm currently doing History, Government & Politics, English Lit, and BTEC Law. I'd say don't take A-Level Law. I just take it for BTEC because it's interesting and it's an easy UCAS booster, but I intend to drop it next year if I can't carry on with all four.
You'd do well to take some essay-based subjects. History, English Lit, Politics, all good for that kinda stuff.