QUOTE(sarah123 @ Feb 23 2008, 03:28 PM)

I've spoken to a couple of people doing music. They seem to think that I'd be able to do it, but that, like you say, the composing bit is where i'd be most behind.
In terms of the quality of teaching, i've been looking through the prospectus and 21 out of 33 people got As last year, so it must be pretty good.
Wow it sounds like the teaching is good - I'm amazed at the amount of people taking music at AS...in my school there's currently only about 6 people doing AS and only about 3 doing A2! And the teachers in my music department are good!
I think you should go for it. My A-level prospectus says that GCSE music isn't necessary to take the a-level music course, and that a high level of performing is needed, with an interest of different styles of music. It sounds like you are at a high performance standard, and are really interested in music, so should be able to do well.
Do the music teachers in your school know about your musical abilities? If so, perhaps it might be useful for you to ask them their opinions on how you'd get along with the course.
As people have said, the composing side of things may be slightly lacking if you didn't use Sibelius software for GCSE, but it isn't too hard to use, and your teacher/other students in your class will be able to help with where to find all the symbols and everything. Your grade 5 theory will be extremely beneficial, as others have said, as you will already know about cadences and composing melodies etc...
Good luck with whatever decision you choose!

Laura