To give you a rough guide, i was pretty much bang on 300 quid for my cbt, theory, lessons and test/hire of bike. I only had 3 lessons which kept the price down, worked out a good bit cheaper than doing the 3/4 day course too.
You're over 21 and if you do the direct access you can ride anything. Good shout on the gsxr, that's what i have - cracking bike.