Sabre,
If you have the chance to go to Uni, take it. They will be the best, booziest sex filled days of your life. Along the way you might even pick up a useful qualification that will help you into a career just in case the flying thing doesnt work out. You will also have the chance to apply for the UAS,where you can get a feel for life in the RAF and get some free flying at the same time. If the UAS isnt for you then between hangovers and studies you could get a job at the local flying club working as the ops bod/washing planes/fueling planes etc. etc. this will give you a feel for General Aviation and the possibility of some cheap(ish) flying (maybe).
Dont close down all your options by not going to University, if you are only 17/18 then a 3 year degree will see you graduating at 21 and ready to take on the world with some letters after you name. 10k of debt is NOTHING compared the sums of money it takes to self sponsor yourself through a CPL/IR (frozen ATPL) course of study. Consider that the cheapest possible way of gaining a JAA frozen ATPL will leave you with very little change from 35,000 pounds a mere 10,000 is neither here nor there
If you are considering a course of professional pilot training, get a Class 1 medical before you do anything else and apply for all the sponsorships that you can find.