TalkinPeace can you link me to "all the research and data" about class size and outcomes, or give more information please. I don't understand what you mean by "levelling" and where is the research that "levelling, discipline and extra adults" make the difference.....and what difference?
I'm always wary when people talk about "all the research says" because there is rarely a consensus of opinion on research issues and ime research on any given topic varies a great deal, and different conclusions are drawn.
I don't claim to have any evidence about class size and good outcomes at GCSE/A Levels. FWIW I think the die is cast in the first 5 years of life, (especially the first 3 years) as a child will never learn again at such a rate in his entire life. If a child is brought up in a nurturing environment and is stimulated in an age appropriate way, and parents make learning a fun thing, then this gives the child a head start when entering formal education. Teachers can only build on the raw material..........
My grand-daughter said recently how surprised she was when she was in Yr 7 at her independent school (12 in class) when a girl put up her hand in the maths class and said "I don't get that Mrs X" and the teacher spent a long time explaining. My GD went to a state primary whereas most of the girls in the senior school had been in independent ed from the age of 5, and were obviously used to asking questions and being given explanations. My GD said "no-one would have said anything like that at primary..." Again no evidence but thought it said a lot really.
Incidentally I am opposed to private education but it wasn't my call and my GD is thriving and is very happy at school so that's good enough for me.