These replies are brilliant, thank you so much.
To respond a little bit:
Yes, the grandparents who left us this money would be pleased that we'd be choosing to spend it on education (rather than cars / holidays etc..)
Yes, we will still have an extremely comfortable life. Yes, I know we're very lucky.
Yes, we will still be able to help the DC with university / house deposits etc when they're older. This 'school fee' pot of money is completely separate. We've already paid off the mortgage.
Yes, the private school we're looking at is academically excellent but also well rounded. Lots of music, sport, extra curricular activities. It doesn't give off a posh / snobby / exclusive vibe.
I wouldn't be concerned about my children turning into posh tw*ts, mainly because I wouldn't I let them...
The state school that we are in catchment for is OFSTED Outstanding.
It is massive. Two thousand plus students..ten form entry. Every class is a class of 30. It's a lovely school though.
Kids are bright and able. They aren't off the scale, but doing well at primary school. There's a small amount of coasting going on.
I'm most interested to know whether they will do 'better' with a private secondary education, rather than continue to coast...
I WOULD expect more of my kids if we were choosing to spend this money on their education. Is that a good thing or a bad thing?
I WOULD hope for confident, well rounded, happy young people who are able to hold their own in the world at the other side...