During 1941 Captain Anthony Quayle lead Auxiliary Units in Northumberland. Although he probably visited Coleshill House he was not part HQ Staff. He then went to Gibraltar and was involved in the planning of Operation Torch. Later he joined SOE and was dropped into Albania.
See these to links for more information:
On page 228 of John Warwicker's book "with BRITAIN in MORTAL DANGER" Dorothy Rainer ATS SD Signals is quoted as saying " ...After this we came Wilton Castle in Southern Command with Anthony Quayle as IO...."
I missed this thread before.
As mentioned Anthony Quayle seems to have started out as IO in Northumberland where he was fondly remembered. He was there from 1941 to mid/late 1942 when Victor Gough replaced him. He then seems to have spent a while a Special Duties IO, which interestingly he overlooks in his biography. He then went to Gibralter as ADC, a job that Major Peter Forbes apparently recommended him for, by Forbes' own account. I don't think we have any evidence so far that he was ever a member of the staff at Coleshill.
The picture in The Last Ditch is the only wartime one of him I have seen.