re apprentice.....
there's a coule of ways you can go to becoming a controller. the first and most direct route is to apply to one of the larger ATC providers eg. NATS - check their web site for what qualifications they require etc - when i applied it was 2 A levels and 5 GCSE's but that may have changed since they lowered the wage! if you get accepted and pass all the tests they train you either tower, approach or area depending on their requirements so you dont have a say as such.
the other option would be to get a job at smaller airports eg. southend as an air traffic controllers assistant with the chance of then being trained up.
good luck