Everyone always talks about London, but misses out some of the other cities/large towns.

Manchester maybe a better option than London. Manchester is cheaper and has almost all the things you want from London without a lot of the negatives. Pay isn't nearly as good but the costs of living in Manchester are about 1/2 to 1/3rd of what London is.

If you want better weather the south-coast has Bournemouth (lots of smaller to mid-sized companies that do web development and insurance).