I was using hit btc and they dont allow withdrawal to a bank account - I had to send back to Coinbase and then transfer to my bank account however Coinbase require a fee to setup the bank account..thats the only reason lol
Try kraken.com ? I've used them for euro SEPA transactions, and only paid 0.09 EUR fee per transaction. I can't check if they offer GBP withdrawals though, as my internet provider seems to have routing problems at the moment.