If you can live anywhere in the UK, then you can quickly narrow things down by cost, and transport links. Will you want to travel much or will you need to access any particular place regularly? Many places are gorgeous but not massively well served by transport, Cornwall for example. Rents will be influenced by transport links and by availability of work locally. If one or both of those don't matter, you probably don't want to pay for it. If two places are the same rent, obviously the one close to work/transport will not be as nice as property as the one lacking those.
Also, what kind of property do you want? If you want the property (excluding location) to be as nice as you can possibly get for your money, you need to go for an area with cheaper rents, but not so cheap that it reflects an area where the type of property you want won't exist because no-one can afford it. Also, think about the type of community (if any) you want to be part of - you might be able to live remotely, but being nearer centres of employment might increase the amount of other people around.
Given all that, I'd ask - do you want to be in a town/small town/village/totally rural? Do you have any preference for the local countryside, eg. wild looking moors or Cotswold villages...coastal or not?
Do you have any big interests or hobbies that might play in?
This is fun! I wish I could choose anywhere.