Check out the ACM website:
www.acm.ac.uk. That'll give you all the info on the courses and entry requirements. You basically send in a audition tape and form (downlaod it from the website) and the tutors will assign you to the course they think suits your abilities. For the degree, I think they do look at A-Levels, but if your playing is good enough, I don't think they care too much for a music A-Level - they say your playing should be of Grade 8 Standard, and having Grade 5 Theory or above is also preffered, but these are guidlines more than prerequisites. You might want to phone them up just to check that.
Of course, you could do what I did, and go through the Higher Diploma to get to the degree, but to me it sounds like you'd be more into the Degree programe - I'm deffinately enjoying the degree more than the diploma (not that the diplomas are bad!).
As for inspiration, well the ACM hasn't let me down there. The standard of musicianship is awesome, especially on the degree, and that's the students I'm talking about. It's quite intimidating at times sitting in a room full of younger, more talented players than yourself! But that's the kind of inspiration I need. The teachers are phenomenal - not just good players, but good teachers too: very friendly, encouraging and they never talk down to you. Everyone - the students, teachers and the rest of the staff - is really nice and down to earth; there's a really great atmosphere here.
On the degree you get four two-hour lectures a week, and than as many one to one tutorials as you can book (they fill up real quickly - I normally get two a week). You can also book out practice rooms etc. Written down, that might not seem like too much work - I'm only in the college for 9 hours or so a week! However, thislgives you a lot of time for practice and course work, and trust me - there's a hell of a lot of work to do!
On the diplomas, you get twice as many lectures a week, but then less time to practice! Also, the diplomas really feed you the information needed to pass the exams (which are not really that difficult if you've put in the practice), where as on the degree they expect you to work a hell of a lot more stuff out on your own.
Sorry for the huge post, hope the info helps! If you have any more questions, feel free to ask!