Today it does sound incredible.
When I went to school it was life as we knew it, and it was the same for me as thousands of UK schoolgirls during the sixties.
One of the factors we forget is that during the sixties in the UK many single-sex schools were being combined.
This unfortunately in practice often meant that the Headmistress of the very efficient girls High School would be displaced in favor of the Headmaster of the school they were being combined with (under comprehensivization).
The disciplinary system would therefore in many cases be biased towards the male ‘Grammar School’ model (itself based on the ‘Public Schools’).