This is from the June 1941 listing. It's the best I can do. It appears to relate to UK Commands. Is the company that you're looking at included here ?
Hi Guy, I suspect you already have this. WO 166/5027 40 Motor Coach Company, RASC. regards.......Graham.
Graham, Thankyou, I have discovered that all the Motor Coach Companies all became Troop Carrying Companies at the end of 1941. Guy