old British TV

Been going over some old British TV lately. Which led to a number of strange ideas.

Has UNIT or SHADO ever had to call on International Rescue for assistance?

Has either organization ever needed the aid of John Steed and his various companions?

What does SHADO think of the Doctor?

Is Lt. Harrington at SHADO's moonbase an ancestor of duchess Harrington?
(I really hope I someday get a chance to ask David Weber that one. :-)

And scariest of all...

Has the Doctor ever encountered Sapphire & Steel?