OK, I’ve looked it up. For those interested: "It was decided that those born on or after 1 October 1939 would not be required, but conscription continued for those born earlier whose call-up had been delayed for any reason. In November 1960 the last men entered service, as call-ups formally ended on 31 December 1960, and the last National Servicemen left the Armed Forces in May 1963“ The date of actual call-up had been pushed back from 1957 onward, which I’d forgotten when I made my orginal posting. For some reason the last few servicement had to do 2.5 years, probably to take account of the ending of the compulsory reserve commitment.
I was born before the cut-off date but was still a student when conscription ended, so avoided it!