In Bethan Roberts' 2012 novel My Policeman, Marion Taylor begins working as a schoolteacher in 1957. She writes her name on the chalkboard for her students:
A moment passed as I gathered myself, then the chalk touched the slate and began to form letters; there was that lovely, echoey sound—so delicate and yet so definite—as I wrote, in capitals:
MISS TAYLOR.
I stood back and looked at what my hand had written. The letters climbed towards the right-hand side of the board as if they, too, wanted to escape the room.
MISS TAYLOR
—my name from now on, then(p. 21)
In March 1958, she marries Tom Burgess. She is generally referred to as "Mrs Burgess" from then on; Tom signs them into a hotel as "Mr and Mrs Burgess" (p. 88), and the counsel for the prosecution at the trial of Tom's lover Patrick addresses her as such:
Mrs Burgess, I would like to read an extract from Patrick Hazlewood's diary to you.
(p. 124)
Marion's marriage is not a secret among her colleagues, and there is no indication that she keeps it from her students. However, the schoolchildren apparently still address her as "Miss". In July 1958, which is presumably during the next school year, one of Marion's pupils calls out to her:
"Miss, Milly's crying. ... I think she's wet herself, miss."
(p. 102)
I would have expected the student to address her teacher as Mrs Burgess or Ma'am rather than Miss. Were female teachers in the 1950s referred to as "Miss" regardless of marital status?
References
Roberts, Bethan. My Policeman. London: Chatto and Windus, 2012. Epub version 1.0, ISBN 9781448130986.