Hi Lucy, unfortunatly I don't have any direct expertise in the area of art and design, so am unable to give you any specific advice, though I will give you some general advice on how to go about choosing a course.
Firsty if you've decided you want to do design and philosophy you are a good part of the way there, some people come out of school with no idea what they want to do a degree in! The next stage depends on how sure of the choice of degree you want, if you are very sure you want to do design and philosophy (I'm assuming this is an actual degree as opposed to just an idea of what you might be interested in) you need to start looking at universities where it is offered. As it sounds pretty specific, I would think only a few universities offer it so find out which ones do on the UCAS course seach fist.
Assuming there is no specific course you want to do, but you are just vaugely interested in design and philosophy there will be courses like this offered by lots of universities - and obvioudly you can't check out everyone so you may want to consider the individual universties first and when you have narrowed the list a bit you can think about courses again.
First look at the university leauge tables at the Times' website http://www.timesonline.co.uk/article/0,,...36,00.html and find some universities which are similar to your predicted grades, you can also check out the Guardin's leauge tables by subject http://education.guardian.co.uk/universi...3/0,13330, 956807,00.html which will give you an indication of which ones are good for design and philosophy. Then use your own criteria (city or campus, sports facilites, accomodation prices, closesness to home) to whittle the list down further.
You should now have a small group of universities which you can investigate futher, look at their websites, go on opendays and order prospectues to decide which ones you like.
Sorry I couldn't specifically answer your questions, try asking them on the Uk-learing message board http://www.uk-learning.net and people may be able to help.
Good luck
Tom