At my School with the teaching staff ( in those days ‘Masters’ and ‘Mistresses’) it was ‘Sir’ or ‘Dr’ ,with Matron as ‘Matron’ or ‘Miss’. When Miss F arrived there was a curious piece of sexism : she was , of course , as a Ph. D, entitled to Dr.- but for some reason that seemed to stick in the throat of some staff, ( we only had one other Dr. ,: the Head of Chemistry), and in any case she was , of course used to the southern ‘Ma’am’.
I’m afraid this was something at which I needed a little practice. Knowing her well outside the school , as my girlfriend’s Mother, and as I played in her Country Rock group , we had agreed to call each other by Christian names ( quite radical for a parent in the 70’s). She used a shortened form of mine which is prevalent in the States , but was uncommon at the time in Britain.