Do whatever the hell you want to at GCSE. Its more important to enjoy your time at school. Seriously, the only thing you perhaps should do is a language - the rest is up to you. A level is when choices matter. Seriously i cant believe you know what you want to do at uni, even where you want to go. have you even visited a uni ever? English is one of the best degrees to get, it demonstrates alot of skills and ability so there are alot of jobs from it, teaching, journalism, script writing for films, theres so much from it. By the sound of it you'll enjoy english at A level and Uni so good luck with it.