I was also quoted £5.50 for international delivery, which again isn't bad. The problem for me is that they wouldn't accept any form of payment other than direct bank transfer, and insisted that it had to be in Pounds. Which for me means another AU$60 (~£35) in bank fees - more than twice what I'm paying for the units themselves, so all of a sudden they are completely unaffordable. The banks also offer a less competitive currency exchange, so you end up paying a bit more for the pleasure. It also means having to go into the bank in person, mess around with bloody SWIFT codes and international bank account numbers, etc. Last time I did it, I spent an hour and a half in the bank.
Honestly, I think if you are going to deal internationally then you need to at least accept card payments, or have a PayPal account or something like that. Bank transfers are a pain in the ass at the best of times, let alone internationally. But I digress, they've been in the game for 15 years, so it's obviously working for them. It just isn't an option for me.