Private school vs State

[MummyHLondon]

Reposting here as chose the wrong thread previously

My two eldest are in a well rounded private school, with good academic results and good pastoral care (London).
They are both bright children with different personalities and approaches to learning.
The eldest (13 Yr8) doesn't do much and still excels in some topics (history/ geography/ rp) but doesn't shine in maths and science which is fine by me.
His brother (11yo Yr6) works much harder (eg will be doing his hw till 9pm if needs be) and takes more advantage of what a private school offers in term of clubs and sports.
Our family has been going through a lot recently which has made me change my mind and being less caught up on a lot of things.
I am thinking of moving them to a new free school which is two years old which offers the IB. IB is of interest because of its international aspects as it's unlikely they will stay in England past 18. They have US / European passports and will most likely want to explore universities abroad.
Their father and I are separated and we split the cost, eg 17K each/ year.
The idea is to - at least for the eldest - move him to that free school and put 50/60k for him aside for when he is 18 that he can use for a deposit for a flat/ start a business, etc.
I just think that the money will probably be best spent that way and that if he is meant to do well then he will.
We are still undecided for the 11yo. The 13yo is ok to try.
Their father and I (plus many other people) didn't go to great schools or eve great uni and still did well job-wise. I also have many examples around me of people who went to private schools and are now in not so great jobs.
What are your views on this?
AIBU to want to take that gamble?

What is the free school like? Mine are in state and will go private at senior based on the local primary being great and secondary being awful.

I have never known a child to be taken from private to state and do well sorry. I think the culture shock was too great. My cousins tried to move her two boys as they struggled with the fees and had to move them back within the year. Ditto several other parents I know.

There is no issue with state but that doesn't mean your kids will be able to adjust.

Generally, if a child is happy at their school then I would recommend they stay.

However, if you can't afford it / think the money could be put to better use then yes, move them.

I personally wouldn't though as the free school hasn't established itself yet.

We live in a grammar area so it’s pretty common for kids to do private primary and then state (comp if they don’t get grammar) or state primary and then private if they don’t get grammar.

I have one dc at private and 2 at state. I have chosen the right school for each child. There isn’t a best school for everyone. It may be the best thing OP, to have one state and one private, or both state or both private. There is enough variation in state schools and in private schools that it’s hard to know if it would work in any specific set of circumstances: you know your dc best.

Thank you for your replies. Interesting to hear the feedback.
The new school is still tiny (only year 7/8) and has an interesting philosophy. It is five min from our house (the current one is 10). I would not move them to a huge London state school. I have nothing against it but I think they would struggle having been sheltered in private education.

Thank you Krog. Most useful.