The standard offer is AABc but I think the competition is pretty tough. I read on the site there is something like 11-14 applicants for every place for history and joint school places and there will inevitably be a substancial amount of self selection for a uni like Warwick prior to application.
That said I think a lot of it is down to luck, a friend of mine (old primary school mate, now attending a selective state grammar) got 10 A*'s, 1 A at GCSE and four strong A's at AS (297 in politics) and got rejected within a week of sending his application off. My grades weren't as strong as his (at GCSE at least - 7A*s, 3 A's and AS 3 A's 1 B) but I got an offer within a month.
I doubt this is much use to you, but I guess it just shows that even the strongest of candidates are missing out so it must be significantly down to luck, don't fret therefore if an offer doesn't turn up.