Corian I have friends teaching in the private sector,that certainly isn't the case. One of my friends teaching in the secondary private sector says she's teaching some real shites at the moment. She thinks it's because they know their parents are paying for it so feel they can do what they like.
I have a friend who taught in one of the top girls boarding schools(she's now left) and she said she saw some really bad teaching.
Some teachers(not my friends and not all)go into the private sector because they feel they can't hack the state system. The small class sizes are an attraction from a teaching point of view if you're not confident. I can remember friends at college considering this for this very reason.
My sister had a boyfriend who also taught in a top boys boarding school-didn't have a teaching qualification to his name,wouldn't have wanted any of my kids anywhere near him incidently Oxbridge degree or not.
My kids are at an outstanding state school,my friends dc are at the local pretty mediocre private school. My kids are streets ahead. She fell hook line and sinker for the attractive leafy building, grounds and glossy brochure but is just too much of a snob to pull them out even though the bills are crippling.
As Violet says you get fantastic state and private schools.You also get dire state and private schools.Fact. Paying for it sadly doesn't bring guaranteed excellence along with the hefty bills. Parents paying for a private education who don't except this are fools.