Dave,
A good USA SureFire Dealer will be able to tempt you away from SureFire.com
If you have friends who can bring you stuff back from the USA then great.
Regarding UK SureFire Retailers,
People gotta make a living and that means making the best of the situation.
We don't have a large market for SureFires and other premium "Tactical" gear so there isn't the pressure to force down the prices.
I've not used Heinnies but I've heard of them.
In fact, I've not purchased SureFires flashlights recently from the UK so that's why I suggest you find out who the hottest Dealers are at the moment over at BritishBlades.
I've considered using
http://outdoorsuppliesuk.com
I get 5.11 clothing from Niton999. I have no real need to get any of the SureFires they stock but I'll likely pick up some SF123As with my next order of 5.11.
From what I gather (although my info may be incorrect), Edgar Bros may be approachable certainly via BritishBlades for purchasing SureFires.
Sorry I can't be of more help.
Al
P.S.
I am a great believer of paying a premium for goods that can be posted to me from stock rather than saving a few quid and having to wait (I don't like to wait).