DUDE!!! HOW MANY TIMES DO YOU NEED ME TO TELL YOU??????????????????????? There are no American sites as cheap as zipzoomfly or newegg that ship to the uk. Sure you might find some sites with an occasional deal but mainly there are no other sites. If there were sites that cheap they would be popular like newegg and zipzoomfly. Like I said a good site many people recommend to people in the UK is http://www.overclockers.co.uk
You think any hardware enthusiasts in the UK would be buying from that site if there was some place as cheap as newegg that ships to the UK? The best deals you are gonna find are gonna be on a UK site 95% of the time. I'm sorry you're just gonna have to face the fact that you are gonna have to pay more then americans.
I believe you were looking for a 7900gt right? well what do you know our own british site has one that would be less then $300 in america. It's not that outrageous of a price. I also believe tigerdirect has a special section for uk customers. It's not called tigerdirect but is owned by the same company and they charge outrageous prices for there items.