Ok. If the priority is commutability to the schools and top state options for your son, then I can recommend my neck of the woods, ie Sutton and surrounds.
You would be in London, but it’s the safest borough and some of it is very leafy with the countryside within walking distance.
Woldingham School wouldn’t be commutable from here but Streatham and Clapham HS is 15 mins on the Thameslink from either Sutton or Carshalton stations. There’s also Sutton High School (a GDST school too) so you could possibly enquire about places there.
www.sutton.gov.uk/downloads/file/4070/schools_in-year_vacancy_checker
The LA regularly updates the list of vacancies in the schools. As it’s n1 in England for secondary attainment and not far behind for primaries, you stand a very good chance of getting a place is an excellent school for your son.
In terms of the areas to live, Sutton has a large, busy town centre but it gets very leafy quickly on the south side. The south also borders the Banstead Commons (accessible countryside) and there are fields etc with footpaths and bridleways.
For a more villagey vibe, Cheam Village is 1 mile to the West. Both locations will work well if you’re after a larger house with a sizeable garden although it’s more of a long-term owner-occupier family area so there are few rentals.
Carshalton village is very pretty with a great sense of community and lots going on. Suitable if you’re after a smaller house.
Generally, it’s very family friendly around here with lots of sports clubs and outdoor activities, leisure centres, a David Lloyd (premium family health club), cinema etc
Alternatively, you could, look in the south of the borough of Croydon, eg Purley, Sanderstead, Coulsdon etc They’re all very leafy, safe areas and some should be easily commutable to either school. State primaries on that side of the borough are good. Some other parts of the borough can be a bit iffy in different levels but you’d be miles from them.