The Mood Modern book gives a couple of dates.
P. 42 mentions the first KP 78s were made in 1957.
P. 56 mentions that library catalogs were reluctant to change from 78s to LPs even by 1966 because TV studios preferred cuing up records with chinagraph pencils while LP grooves were too tiny.
P. 79 mentions after the launch of the KPM 1000 series, Robin Phillips wanted to convert the 78s to brownsleeve LPs in 1970. Aaron Harry was pressed into making the compilations and masters in the edit suite cutting tape.
I have a couple of KP/KPM 78s and they do give dates on the label like 1960 and 1962.
I also have a couple of sheet music arrangements published by Peter Maurice Music (the M of KPM) which were published in MCMXLVI, not sure why they used Roman numerals but that’s 1946.
They have the same titles and melodies as heard on the 78s, but they are full 7 part arrangements which will take some time in transcribing.
Perhaps in the 1960s, they went digging through Maurice’s back catalogue to find something to record.
