Why not just buy on one of the exchanges?
Unless you want to wait 3-4 days for a bank transfer to got hrough (which considering the bubble could burst at any time is waaay to long) its very hard to fund an exchange from the UK. I'm struggling with this as I'm keen to buy some BTC asap.
My last SEPA from UK to Bitstamp went through same day, today's is taking longer.
You can avoid extortionate bank charges and exchange rates by using Transferwise -
http://transferwise.com/u/054b