I found it cheaper to use the U.S. Postal service. I've shipped items to England, Australia, Russia and Ireland with no problems.
You have to fill out a customs form but he pays the "duty" over there. A lot of overseas buyers will ask you to declare it as a gift, so they won't have to pay taxes, but you run the risk of it being confiscated if customs doesn't believe it or wants to investigate. If he paid by paypal he would get a refund because the product was never delivered to him.
A quick quote from the USPS website says a 40 lb package for Great Britain and Northern Ireland, $143.93 if you print the postage online. 151.50 if you do it at the Post Office. 6-10 days.