I must warn people with BTECs now, do not try Birmingham unless you absolutly must, our tutor has already warned us it will be a waste of a choice
Why? Well, she's been argueing with them for a while now about it, but apparently, they highly disfavour any BTEC students, at least for CompSci. You need be able to show them that you are perfect to the course (over all the other applications), and even then, if they do think about considering you, they generally hold off interviews for BTECs until all the A level students have been offered places. Over the past few years, she only knows of 1 student who applied with a BTEC and got an interview (at the interview they impressed them so much, they got the place though.)
Meanwhile, i'm in the same boat as you in trying to decide where to apply to, or even, if I even will go to university now. Got a B in maths myself, and currently doing a BTEC in software development