Can I change schools a term into year 12?

Hello! I'm in a bit if a situation, and just wanted some advice. Im currently a year 12 student doing 4 Alevels, (Maths, Physics, Econ and Geography) but the school I am at has suggested that i drop down to 3 subjects, so I can better focus on 3, I was given a B as a form of predicted grade for physics, so school is suggesting this is the subject that i drop. However, i dont want to drop physics, and do want to continue woth my 4 Alevels, but my school is not willing to let me do so, and is pressuring me to drop before the christmas break. The trouble is, i want to do a STEM based degree, something along the engineering side. So, I was talking to my parents, and they were wondering if I would be willing to apply for other schools/colleges that will be more willing to let me sit 4 alevels, but im not sure if any school would even allow me to apply now (im in london btw) or if it would be a stupid decision to change schools a whole term into year 12.
Any help or advice would be appreciated! Thank you!