It certainly was the case in the early 80's that you had to validate at another unit before going to LL.That was with people that had done the Radar ticket as well.
Also the training system in place now at all Nats units does slow the process down.All the hoops that have to be jumped through,and it takes about twice as long.
I heard a little rumour that it takes about the same time to get through EGPD now at ab initio stage.Mind you it's got 4 runways and 4.5 terminals.
