You can shop around as there are a number of such services. Also you do pay import tax (you have to provide a copy of your receipt) so there's no avoiding that (as there is with Abstract Ocean it seems). So as well as paying for $30 post from Rimetrix to your US address you then pay for it from there to the UK, plus tax etc - I was slightly surprised that it came to £126 - however compared to the cost of 19" a wheel upgrade its still a bargain.Maybe I'll give it a try. I really want a set, but I've never used any of these forwarding services and a Google search didn't fill me with confidence.
Also... Did you create the "free" account? I gave it a quick try but it wanted to charge me $1 when it forced me to add a PayPal account during account creation - so I cancelled the setup. I couldn't find anywhere to explain what that was, or what I was signing up for exactly, that ambiguity and the reviews made me a bit nervous.
I used the free account and it worked fine - no charge. Rimetrix were very quick to dispatch and when the package arrived at my US address I wondered how long it would take before it was dispatched to me and I (optimistically I thought) emailed them to ask - but got a very immediate and helpful reply. The package was dispatched a few days later and arrived safely.