My experience, which is not the UK experience, is that the duties are not the big deal. It's the shipping. Try not to have a courier type company but a national carrier. From the US, insist on USPS. Doesn't matter what version, you'll do better. Here's why: first, customs processes it randomly, you might get hit, might not, courier will; second, if you do get hit, there's nominal broker fee which is a fraction of the courier types; third, tracking works with USPS, just remember once it crosses the border/custom, it's now on your postal system, the tracking number stays the same.

I don't think there's any advantage to a consumer to use a courier unless it's a big hurry, and I've seen that screw up too.