rd_boulby,
Hi mate! As most of the other guys have said you've got a great basis on which to start building for a career as an airline pilot. Getting good A levels is a must, and although most say you defintely need maths and physics, this is untrue. If you get A's in something you enjoy, this is better than a forced C or D in Maths. Although it is important that you have some ability for mental arithmetic. You'll most probably need 2 Alevels should you wish to apply for some of the 'sponsorship' schemes such as Netjets, Thomas Cook or Excel through Oxford Aviation or other schemes such as FlyBe through Flight Training Europe (FTE). Have a look on their websites and see what you can dig up. Uni is also a big help to sponsorship schemes and again I'd say do something you enjoy, after all 3 years can be a long time doing something you don't like. Alot of people say a degree isn't worth doing either, but if you lose your medical, it can be mighty handy as a fall back, not to mention the personal development you'll get at uni. An Engineering degree is always a good fall back, but it is a challenge. Also, flying at your age is a great way to gain experience and shows willing, something that the airline schemes will want to see. Do everything you can to show you've made the effort, it will pay off big time in the end. I'm starting my training in August, after 5 years of uni and I can't wait!
Any questions, drop me a line.