Hey! i know exactly how you feel. I also have geography coursework, but it's a level and i hate one of my teachers! (also basically in y13 we're allowed to leave early if we have study last, but based on certain factors like subject teachers, tutors, parents, attendence+punctuality, and even though everything's good, 100% attendance+no lates, my geo teacher wants me to stay p5 so :/)
anyways, have u told anyone else? imo its always good to talk about it, bc there are a lot of people who can talk about it. And you can always talk to Head of Year or form tutor about THAT teacher and they'll hopefully sort it out with you. And don't be afraid to ask a different teacher or your parents for help (or me, @ on inst is Sirius _ stuff)