EXCLUDING courses such as ADR, LGV driver training etc that were already in force and have had periodic DCPC hours attached to them, what percentage of new useful info did you learn?
This refers to courses that were devised to give periodic DCPC hours such as tacho regs, customer service etc
Zero 
I reckon I learnt one or two things on each of the 4 different courses I sat. On the 5th all I learnt was the trainer was a not very clued up agency office bod. Make it tested, with an 80% minimum pass. That would soon sort who actually already knew what they were being told, and who just thinks they know it all already.
I learned how to drive a forklift, over four days, which was four days worth of CPC. I haven’t driven one since and don’t intend to either.
I did another day in the classroom annoying the instructor with smartarse comments.