I don't know how this might work between the UK and the US, but I just today went to a place called Intercash, located on the 3rd floor of Elys Department Store in Wimbledon and managed to get them to send £100 directly to my bank account in Sweden, so I can get some standing bills paid. The cost was £10. I had asked at my bank, Barclays, and was told they would charge £45, I believe it was, and it was better if I transferred a larger amount since it would cost the same.
Me, I do NOT understand anyway the huge bank charges for things like this, both in the US and UK. In the States, when I transferred money to my Swedish account when I moved there, they wanted $45. Barclays (and I assume other UK banks are pretty much in line with charges) wants £45 to transfer money to another bank within the EU. Yet when I moved here, my Swedish bank gave me all the information and should I need to transfer money from Sweden to my UK bank, the charge is 15 SEK, which is about £1.25, give or take.
We are not talking tiny unknown banks or building societies here and this is the computer age. I know for a fact that they sit at their computers, push a few keys and bingo, the money appears on the other side of the world. Sending my husband $400 from the US three years ago, it was in his account within a couple of hours.
Anyway, enough of my financial tirades, if you're in south London and want to send money at a reasonable rate, try Intercash, offices in Croydon and Wimbledon, open 7 days a week!