Congratulations Old Duffer
It sounds as if you were instrumental in getting a miscarriage of justice rectified.
I remember doing the course in the winter of 64/65, snow on the moors and bloody cold, wearing just overalls and plimsolls as you said. We heard following the death of MP Howarth that if the sea temperature went below ?degrees students would wear immersion suits. I did the course at least three more times (twice in winter) and I certainly never saw sight of an immersion suit.