http://myweb.tiscali.co.uk/radar2001...rces/ATCO1.htm
This is a site oft quoted here on tips for NATS applicants. Best tip, get out there and visit some NATS units [Swanwick and Southampton are nearest] if possible, but any ATC unit [Exeter or Bristol] if you can't get far enough east.
Don't give up the day job for now, as you won't even be starting at the college for at least 18 months. Good Luck. Post here to let us all know how you fare.