Wren in the UK is it:
http://www.wrenpowersystems.com/

Tony Ratcliff is the head guy now, Mike Murphy is still there as well.
Good luck, they are pretty spotty at communications and customer service.
Payment is only International Wire Transfer.
That said, my Wren44 Gold went there and back last Summer and is fine now and I have recently gotten a new ECU for my SuperSport and that transaction went well.
- Mike