Rank Retention ...
My first boss after I became a civilian was a gentleman of Air Rank in his previous life. Very early in the interview before taking me on, he said: "We're both out of the Service now, John, my name's Tom."
'Nuff said.
If both MM and the Bloggses are civilians, former ranks are irrelevant, surely and normal manners apply - or is village life in UK really based on former glories?