Prolific

hi,
I am after some advice, im about to apply through clearing for Molecular medicine at sussex, my alevels are AAB in law, business and sociology in 2006. This year I completed Alevel biology and am predicited and A. So all together my alevels are AAAB, however im missing chemistry. Would his be a major absticle? did all your class mates do chemistry at alevel? Finally how many of your classmates got into med schools? what med school favour molecular med is it just BSMS and queens? I intend to volunteer in a nursing home throughout the degree for experince etc..
Sorry for all the questions just wanna make sure i make the right decision,
regards