Firstly do not worry too much about your AS grades as I am sheer proof that with hard work and determination you can achieve much better grades in your A levels. I got ABBC in my AS levels (which I was pretty dissapointed with) however achieved AAAB in my A levels (and a B in general studies but we do not include this.) The reason I did 4 is because my college made us or pick up an AS or do an extended project, none of which I liked the sound of. Plus my worst grade in AS (history with the C) I got an A for this year! (after resitting a paper I got B in AS then C in coursework but managed somewhow to get full UMS in my last exam!) So its a good thing I didn't drop it after all
This year having spoken to many would-be law students for this sep many of them were unable to achieve the AAA standards, as I've said there were numerous AAB's and a fair few ABB's (and thats just in a group with a third of the total law students), a few A*AB and even a guy with BBB. It just goes to show that with A levels getting harder (0.3% less A's this year than last yr) is making an impact, also that people with AAA are actually applying to 'more highly looked upon unis' like bristol, nottingham, london ones and even oxford only want AAA.
They will defo consider you and I'm 99% sure they'll give you an offer so I wouldn't worry much about that (many predicted AAB/even ABB were given offers of AAA)
I think personal statements do make a difference but as long as it is adequate and you emphasize exactly why you want to study law (stressing your passion for it etc) then you'll be fine
Nah oxbridge only want like 21/42 to be considered and as I've said some people at B'ham have been accepted with 16/17 (I personally got 24 but thats not the point) I don't think the essay makes a lot of difference personally (as mine was terrible with horrific spelling) but it's worth practicing for (I was lucky with a few sessions at college designed for those doing the LNAT, also if you want help/copies of info about this test then let me know)
Yeah if you want a look at my personal statement/want me to look at yours let me know
Sorry for the rambling aha and uber long message. Yeah can't wait to start, and its gone up in ranking for law this yr! You should see the freshers and law freshers stuff as well, looks amaze aha