It was all "new" at the time YL
Hamble was airwork services training until 1960 and prior to that the base of the ATA during the war who ferried the aircraft. The corporations realised that they needed differently trained pilots than those available from the military who had a diabolical accident rate and the 700 hour improver route.
It wasn't just flying training but also training young gentlemen managers as the responsibilities of airline captains (and their skills) were very different to today. Oxford and Perth were commercial operations which took on the overspill and as such didn't have the same level of financial commitment as Hamble. Their graduates were just as good imho although as Hamble catered for mostly grammar school boys I have the feeling that we were hungrier and more malleable which is what an employer wants. We put up with more of the bull****. But in the 70s BEA was haemorrhaging pilots.
100 hours! The Lane inquiry criticised our 225 hours as being too low. Nowadays 160 hours and no twin solo is deemed acceptable ( which doesn't include spinning). Of course we have a level of automatics, serviceability and information that was unheard of 50 years ago but when you look at Air France 447 you can see how horribly wrong it can go when you dont have crew with the required professionalism.