Wow, this went off topic quickly,
I went to private school when the fees were 10k a year (now more than 50). I see the argument both ways but wanted to clarify a few points. Clearly from the number you see above the school I went to won't struggle as it is at the more exlucive end.
Payment in advance works (my fees were paid this way by inheritance, yes all of the inheritance) due to the school which is a charity being able to invest it and not pay tax on the gain, hint, that's why they used to be able to offer a discount more than you can earn by investing it.
Big private schools do all sorts behind the scenes which they don't shout about, hint one thing you learn is to not be obnoxious and to treat eveyone with respect.
People who send their children to these schools actually save the government over £6k a year by not taking up a state school place. These pupils, if they do well, then go on to pay university fees and a lot of tax in work.
For anyone who says that people who can afford the fees can afford the VAT, this is categorically wrong. The parents of my best friend at school could no way have afforded that increase, they struggled for 5 years to keep him there. To be a contarian and take it to the extreme, let's say anyone who can afford to live off benefits can afford to pay 20% tax on their benefits. Clearly not, if money is tight then that's the situation.
People confuse rich and wealthy, making sacrifices and living easily. This isn't a one size fits all and it will harm kids mostly. Just like I don't want to see my kids struggle at school (state btw), I don't want any parent to have to go through that scenario. I don't begrudge people who can afford to send their kids to private school, that is less pressure on the state school where my kids go and to be honest who could afford 6 kids at fee paying school a year.
For info my partner was a teacher in south america and taught some kids in a shipping container in a favela (45 degrees in the shade) with one fan for the whole class. They all learnt well. That's because they wanted to be there and saw the value she was providing. She was never disrespected or had any trouble, the problem could be down to kids now expecting someone to learn for them. Kids are parent's responsibility with schools providing specific learning support. Government should make parents responsible and let them do the best for their children.