Dental hygiene + therapy

I’m currently doing btec applied science (worth 2 a levels ) and psychology a level . I was wanting to do dental hygiene and therapy at Leeds university but there entry requirements are that I have a my btec plus a level biology . Which caught me off guard because I’m doing btec because I didn’t meet the entry requirements to do a level biology . Even when I asked my teachers if I can do it they said it wouldn’t be a problem however it’s a timetable clash . How would Leeds university respond to that since I’m sure there are many students who also can’t take a combo like that . Like why would Leeds set their entry requirements to something that isn’t really achievable to most people .