Is that predicted grades? Cos you could really do with trying all you can to end up with AAB(B) if possible. As far as I know (although I may be wrong) edinburgh are the only place that will accept 4 alevels at those grades. Most places say there is no advantage to having more than 3 alevels, so would expect AAB. If you are only eligable to one place you in a huge case of eggs in one basket and the odds aren't that good! Most people only get one or two offers after applying to four places. So the chances of you getting an offer from only applying to one place isn't that high tbh.
You obviously need to make sure you tick all the other boxes - lots of varied work experience. All the basics and then some different stand out placements if possible. Maybe a long term placement somewhere.
ECs such as voluntary work (doesn't have to just be animal stuff), DukeofEd award (Gold), youth group work.
Courses such as vetsim etc aren't worth the money imo. Over commercialised to the point where tutors won't pay any attention to them. If you want to do courses pick some sort of science or animal course.