Always gotta take one risk with your UCAS! Or else it ain't worth it, you never know although I'd like to remind you you're not guaranteed an A from your remark and you'd need your teacher to give you that A* prediction but do remember it's not completely feasible since you know you're pushing it so keep those AAA and BBB offers on board and take the risk with realistic expectations, academic credentials are just part one of applying to LSE and most applicants have it as their lowest priority. Hope I've motivated you a little but also kept it realistic