Hi there,
Bath has high entry requirements across all of its courses. Aerospace will require AAA* with a strong performance in maths and physics (or an engineering discipline). Your personal statement will also need to show a passion for your chosen subject and a strong motivation to study it. It would be good to talk about any relevant experience - this doesn't have to be specifically aerospace, it could be any engineering or science experience which may be helpful to your course.
Bath, Bristol and Imperial are all highly ranking universities each with their own merits. I would recommend looking through the offered modules on our websites to see if any call out to you.
Good luck in your application,
Sophie (uni of Bath, Civil eng)