Wha do you call a Master Pilot/Nav/Sig/AG/LM/Uncle Tom Cobbley 'n All ?
Rigga, (Your #14 - a long way back !)
"I remember referring to him as "Mister" Riddoch, a term he seemed to like very much!"
So he should, it was his correct form of address (from above and below), as a rebadged Warrant Officer.
(So it was with P/Os and F/Os).
Danny.