I don't feel strongly about this policy either way. We may go private at secondary if our kids don't get into the (phenomenal) local grammar, but we'll probably have saved enough by then to cover any increase in fees due to VAT.
Random musings on this topic are as follows. I imagine it will take a while to see the consequences of any increase as parents with children currently in private will probably do all they can to tighten their belts to avoid interrupting their education. So the effect will be less children starting out at private schools going forward rather than a move en masse to the state sector. If schools close, I imagine parents will target alternative independent schools rather than necessarily needing state places, although that may vary depending on area.
Parents currently thinking about private school will think twice. I wouldn't like to have a Y5 child atm and be targeting an oversubscribed state school as my first choice for them.
Some private schools may choose to "soak up" the VAT increase and cut their coats according to their cloth, rather than charging parents more. So we may see a slowdown in the private school facilities "arms race" that has afflicted some schools in recent years. This is probably a good thing - some private schools seem to have forgotten their original "mission" amongst all the shiny rowing centres and climbing walls. But it's still not going to make these schools affordable for most people.
For those SEN pupils whose parents have watched their spark slowly being snuffed out at the local overcrowded state school with inadequate SEN provision and who have stretched themselves as far as they can go or extended their mortgages/gone into debt to fund provision which should have been available to their kids in the state sector, this policy will be a fucking disaster. I really feel for those kids and parents.
Finally, it's an emotional issue. Some people will welcome the change on the basis that private schools entrench inequality (and tbh I find that hard to argue against). Some people will be upset about the possibility of their children's continuity of education being interrupted, which I can also understand.
Personally, I think the fairest way to implement this policy would be to apply it prospectively rather than retrospectively. So the VAT charge should apply to pupils starting out in private schools, not pupils already there. That way, if the VAT increase will make private education unaffordable for the parents, at least that child will have the same shot as any other child at a good state school place at 4/11, rather than having unexpectedly to move schools to wherever is available. Parents should be entitled to some certainty in making educational decisions for their children.