Teacher basing grades on classwork

Hey there, I'm really really worried about the upcoming grade situation during the corona-virus crisis. I thought I would be fine; my predicted grades are A* A A, I've applied to go to King's College London as my first choice and my backup choice is the University of Glasgow, KCL requires AAA whereas UoG requires ABB. I'm currently doing English, Film and Business, English and Film I have no worries about, both my teachers see me as a good student and I believe they will both give me As based on evidence such as previous exams and coursework HOWEVER, I am very worried about business. My teacher has taken it upon himself to disregard what I achieved in AS levels, disregard what I achieved in my mocks and instead base our grades on evidence from classwork, class exams and stuff. I achieved an A in the mocks and a B in the AS levels and was predicted an A, however I did terrible in these non-official class exams as I didn't revise for them and was heavily drugged up most of the time (I'm not blaming the drugs, but they play a factor), in one of these class exams I got a 7 percent, which he asked me to remind him of recently when calculating my final grade. This really worries me, if I get anything less than a B, I won't be able to get into ANY of the universities I applied for. I really do not think anything less than a B represents my potential since I've always achieved the same or higher in official exams. Is there anything I can do about this? I've heard there might be a way to return grades you don't feel are right because of the situation. Any help would be really great, thanks.