Hello Mark, yes there's a regular UK group that also includes many Americans and Europeans - we have players from Sweden, Switzerland, Germany and one ex-pat in Bangladesh
The group is a sub-section of the UK Kriegspiel Society (
http://forum.kriegsspiel.org.uk/) and we gather to talk on the PC-based Kriegspiels of that forum because of the way we play which is with a POV fixed to the general (Headquarters in the Saddle or HITS) and we use couriers all the time for player to player communications as well as player to subordinate AI units. When two player generals meet on the battlefield we allow voice communications while they are together.
Effectively this gives you a first-person view of the battle with communications problems as close to reality as the software allows; if you are used to playing with a high-altitude free camera view and instant communications to your units you may find it a bit of a shock, and I know it's not to everyone's liking but we're a very friendly group and we meet at 7:30pm most UK evenings and play on as long as people want, which can be VERY late here once the American side of the group arrives to carry on.
Say hi on the KS forum or drop me a PM here and I'll give you our Teamspeak server address and password.