Your plans have been upset. It's a set back but learning to deal with set backs is perhaps the most import life skill there is. Durham is really geared to northeners looking for an Oxbridge type atmosphere up north, without the rigors or inconvenience of getting into Oxbridge. But you're from Wiltshire (so leaving would make you sad) - there are plenty of other places closer to home (Cardiff, Bristol, Oxford, Exeter, Bath, Swansea, Portmouth, Southampton, Plymouth, etc. - if you are posh, most colleges have halls that can provide you with the traditional experience you might seek, just hyphenated your last names and they'll take the hint
). Up north, Manchester is now highly rated. What about St. Andrews in Scotland?
I love Cornwall, it can feel remote (less so in the Summer) - especially inland I am told - but it is a great location, and that is part of its beauty. However, I've never heard of that college let alone that course, is it in the same league as Durham? I would think not even close. Durham was probably a first or second tier University in the old days. Truro wasn't an old University, nor do I recall a Polytechnic down there, so what was it? Local technical college? Don't get me wrong, Cornwall is a great place to build new HE colleges, to balance out the Summer holiday business/traffic and provide a beautiful and tranquil location to learn in. But it looks like you applied to the premier league and the fourth division - maybe you should look around more in the middle ground? But if the course and location grab you, and the standards are good, then that's ok.
I'd suggest that you make sure you gain skills that will help you find work afterwards. Cornwall is fabulous - but you need to know how to enjoy it: surf, rock climb, paint, spear-fish, sea kayak, angling, beaches, walks, pretty girls, visit the galleries of St. Ives, the restaurant if you can afford to - find ways to experience its joys. But you'll probably feel happier if you know you are gaining valuable knowledge/skills too - so, whatever you do, apply yourself (another important life skill). If I went there, I might never leave.