My late FIL, a small scale builder and decorator was once doing some painting at a local big house, home of a member of the peerage.
One day, whilst up a ladder, the butler came in with the then Dowager Duchess of Westminster. They were introduced and FIL raised his paint stained cloth cap and said,
"Afternoon, Ma'am."
Later on, as he was leaving, the butler gently pointed out that one usually addressed a Duchess as "your grace."
FIL replied in a broad Worcestershire accent, "I calls all women Ma'am, then none of 'em gets offended."
His attitude was that we are all equal and that we treat everyone with the same degree of respect.
I'm not too sure what posh is any more. Perhaps it is breeding rather than wealth.
Whatever it is, I'm not it. Common as muck me!