I think when the MRGC came out the 25 wpm was kicked into touch. I took the MRGC in 1975 but since I had a PMG2 at the time didn't have to do the Morse, only the writtens and practical.
Interestingly for the Cheltenham mob plain language was always in a foreign language. To tell the truth I found this easier as you just treated it as code and didn't try to read it which could be a distraction. There was a similar time period for touch typing training but I did a
'brain washing' Sight and Sound touch typing course when I was doing my PMG2 in Leith years before so they let me come in three weeks late on that one. Their touch typing training was that old
dum did e dum de dum didee dum music stuff, pretty naff I thought and told them they should go with the sight and sound strategy.
I was promptly told to STFU, which I did.