Hi Rick,
As I think I've mentioned previously, my understanding was the the UK Special Force (singular) was the build up UK Forces for the invasion of Japan in Nov 45. The operation was 'Downfall', with sub operations: Olympic and Coronet. British ground forces were part of Coronet (as well as Cdn and Aust).
There are several files held in the UK archives concerning the build-up and assessment of requirements for the UK contribution. Judging from the titles, one of these may well provide you with an insight into the 'UK Special Force' and its requirements. I have not looked at any of them, but
ya gotta start somewhere!
We'll all be interested (I will!) in what you turn up, and to see if the theory is somewhere close to the actuality.
Good luck, Mr Phelps! 
Mike