I was on 99; after about a day they told us that the RAF wanted as many of us as possible to go to University. Some left almost immediately, but the rest of us did a whole year as Junior Entry, because 100 didn't arrive until autumn 1969.
We were commissioned a short while after the 'bitter and twisted' 97 entry became Senior Entry. I gather a few scores were settled before we left for 3-4 years....
The old 2 1/2 year Flt Cdt course was actually extremely good. But had I stayed on it, I would have graduated before the fast jet expansion began - and I doubt very much whether I'd have been good enough to fly the Gnat at Valley.