I live in the USA and have not had to pay import taxes on coins purchased in the UK. Agree with your comments on Heritage. I have bought some coins from them and have been reasonably happy with the grading. The Heritage web site is very good and their photos of the coins are excellent so you do know what you are buying. I think the advantage of Heritage is that you are hitting a pretty big market and one which is willing to pay a premium for quality. But the NGC grading is absolutely key here. Personally, I am not big on slabbing but, in the US market, it is a prerequisite to getting top dollar for the coin.