We get ripped off in this country for prices on anything that originates from foreign countries and it has been that way for as long as I can remember. VAT, customs and collection charges are partly to blame but taking that into account doesn't add up to the huge price difference, it would be interesting to see if it works the other way around and how much foreign countries pay for our manufactured products (what's left of them that is). I'll bet they get them cheaper than we do too.
I find that it's useful to identify UK model shops that stock parts for a particular model and use them based on their customer service. MB Models for example offer great stock for my Kyosho and general RC Car stuff and their service is second to none being friendly, helpful and very fast. Pricing is reasonable in comparison to other UK suppliers too. I have also found Wheelspin to be very good and one or two others on occasions but some of the other UK shops seem to take forever to get orders out and as others have commented above I can get my order from Asia Tees quicker sometimes.
The trouble is that we in the UK tend to suffer these high prices and poor service, not doing anything about it, maybe a petition to the Government (even if it is a joke one at the moment) might stand some chance of improving our international trading standards which don't even work within the EU as we pay more for the same goods than most of the other members. The sooner we get out of the EU the better for fair trading for us.