There are a few different ways to transfer money from the US to the UK. Banks will usually do a wire transfer, which is pretty easy but they often charge you a fee, which can either be a flat amount like $50 per transfer, or a percentage of whatever amount you're transferring.
There are money transferring services like XE.com, HiFX, Currencies Direct, or even PayPal. When I had a lot of transfers to do I used XE. They don't charge a fee, but they give you a slightly worse exchange rate than you'd get from a straight currency exchange and make their money on the difference. There was a limit on how much you could transfer with XE, so once when I needed to transfer a larger amount I used HiFX. Both XE and HiFX were easy to set up and deal with, and I never had a problem with either.
What I'd do if I were you is compare a couple of methods to see if one of them gives you an appreciably better deal than any of the others, or is easier, or for whatever reason stands out for you.
You may also want to think about how much of your life is still in the US, and whether you want to leave some money there to deal with stuff that may come up.
I hope that helps!
