Oooh, doing things in reverse!
As far as I'm aware, if you are ordering stuff here from the US, you don't have to pay the UK VAT, but your local sales taxes apply upon import (I think that's how it works over there - it's pretty similar the world over), but no doubt there is someone else who can confirm this.
Your best bet would probably be to email a UK company (maybe even a non-paintball one) and ask them what would be the situation if you ordered product X from them).