You will need to have the person who writes your LoR ‘predict’ your BC and Stats score; if they don’t predict a 5, you won’t have a shot, and if they do predict a 5 and you get an offer it will be ‘conditional’ on achieving the 5 (so you won’t know until early July if you definitely have a place, so you need a Plan B, either another UK uni, or depositing at a US uni). Note that Calc AB is a subset of BC, so you don’t get to count them as 2 APs, and for either Comp Sci or Physics BC is required.
As Haze Gray pointed out, the PAT/MAT are key to getting an interview offer: if your score is high enough you will get an interview. After that it’s down to how you do in the interview, which is a cross between a tutorial and an interactive exam.