To pay for private school instead of moving?

[Gijjjj]

This is a very non urgent conundrum as we have one toddler and one baby on the way.
We live in a reasonably trendy suburb with £140k mortgage left, but expect our household earnings in 2 years time to be around £120k per annum. They are lower at the moment due to part time working / training.
We thought we were ok with kids going to local comp which seemed nice enough but realised the pass rate for getting a 5 in GCSE English and maths is 50%.
Although both state educated we attended schools with over a 95% pass rate, and we felt a bit concerned that we maybe weren't going to be giving our kids the same opportunities we had been afforded.
We looked at a grammar school area but obviously competition is fierce and the comps in the area are then generally worse than the one we are in catchment for now. So could spend a fortune on moving only to not get into grammar.
We thought we could buy a house next to an outstanding state school (with over 90% stats on the same metrics) but we would have to borrow an additional £300k just to have a similar standard of house to what we have now, and that is less convenient in terms of commute and amenities.
We probably would extend the house we are in, but even though £15k per year per child seems galling, would we be best off just paying for private school and enjoying the area we live in otherwise?
Or should we move to an area with better schools?

YANBU - stay put and pay private
YANBU - invest in property rather than fees and move

Termly fees in many parts of the UK are nowhere near this. I pay £4.5k. Do London MNers also think everyone in the UK pays £1m+ for a family home too? Seems like quite the bubble you all live in!

No need now as it's not an option any more 😅 I had been listening to a radio show about how they disproportionately affect women.

We're in a grammar area. DS didn't pass the 11+ as although he's bright the exam tests speed and he didn't finish. He was also a late reader. Comps are a bit hit and miss. Some great some lacking aspiration for the kids.
We've been looking at private and have found that there seems to be a lot of movement at Y9 both between schools and option to move to private. Three years seems so much more affordable than 5 so if he doesn't get on at his school we'll think about something E tutoring to support and then move when he's developed a bit more.

@LostMySocks
So no private 6th form? Instead 3 schools at secondary? Not a great plan in my view. Friendships will be very disjointed. You need to plan money for 5 years if you transfer in y9. If anyone is in a grammar county, eg Bucks, there are no true comps. Between 20-40 of the lical cohort is missing because they are at the grammars. Where there a just a handful of very selective grammars, the other schools just don’t have the very brightest so are more or less comprehensives. All the schools should have ambition though.