Lovely places to live with great secondary schools

I recommend Buckinghamshire - specifically Marlow. The local comp is so good parents often choose to send their child there if they are just passing the grammar school exam. But also several good grammars including a small village grammar and private schools too. Can get into London 50min drive? Large close train stations are high Wycombe and Maidenhead.

I'm in Richmond, North Yorks, and it's lovely here. Excellent secondaries - Richmond School is brilliant, and easy to get a place. Also, SFX gets a great reputation, although you do need to provide a christening certificate to apply.
Transport links to Glasgow and London are excellent from nearby Darlington.
Ripon is another great area with good schools, but I'm not sure what the transport is like.

Durham - in the catchment for the Johnston School.

Altrincham (Cheshire): 15 minutes outside of Manchester, and on major train routes - there's a station in the town.

Voted best place to live in UK (Sunday Times, I think) and has amazing primary and secondary state schools, a few of which are v high in national league tables, if you like that kind of thing. It's a grammar school area, but the non-grammars are excellent too.

We moved to Morpeth in Northumberland last year and it is seriously beautiful and friendly. A really great community feel to it, the prettiest town centre, flowers everywhere, some of the most beautiful Victorian houses I have ever seen, loads of beautiful countryside walks, the beach just a few minutes away. Outstanding schools and a train station with excellent transport links.

Plenty to look at south of Birmingham. Warwick, Leamington, Solihull... all on a train line to London and you can be in Birmingham by train within ten / fifteen minutes for trains to Glasgow.

These areas have some great secondaries and Solihull doesn't have any grammer schools.

Lots of green space around and you have easy access to Stratford, Cotswolds, etc...

Winchester has 3 very good secondaries and an excellent 6th Form college school, all non-selective, easy commute into London too. Beautiful city and fab countryside.

Wirral- (research carefully: it is a place of huge contrasts!!!!) if your children are bright. State grammar system, some single sex.

Another vote for Durham.

Gorgeous countryside, easy access to the coast, really good rail links. Durham Johnston is an amazing school.

Bishopthorpe Road (Bishy Road) area is now very desirable area. Wins lots of awards for community.

I second York. We live in a village just outside and the schools are great. Fulford School is highly rated, large catchment area, as is Archbishop Holgates. There's All Saints Catholic School too. Houses are expensive but I suppose not as much as London prices!
Desirable areas to live in the city are Fulford Road and Tadcaster Road. The city is accessible by foot too.
We love our village and can get into York in ten minutes.
There's always lots to do and see. Festivals and events. Our DC loved growing up here although they have now moved away for work.

St Albans and Harpenden are great for schools etc but if you don’t need to commute into London save your money!

Richmond is great - really good secondary schools - both Ripon and Richmond are yorkshire market towns - probably worth visiting to see whether it is what you are looking for

Ripon and Richmond are both much smaller and more provincial than somewhere like York.
It depends if this is a plus or a minus for you?

Richmond is lovely as a place but don't know the schools

Ripon - both Grammar school and the non-Grammar are ranked as outstanding (grammar been ranked as top school in the north) and range of good undersubscribed village primary schools if you move a little out of the city. Main east coast line half an hour away in Northallerton and a lovely place to live

Durham Johnston school won the Sunday Times Comprehensive School of the Year this year, since you mention you're interested in Durham.

Chester and Cheshire worth considering as very speedy connections to London and also Glasgow via Warrington. But not as nice as Harrogate/Ilkley.

Another vote for Harrogate, I live here and love it.

If you have a Girl then Horsham is a lovely town. The mixed school there is good but the girls school is amazing.

Harpenden / St Albans also nice.

Sorry.. just saw your thoughts on grammars. I believe non selective state provision is also good. Also worth noting that northern grammars seem less intense than their southern neighbours. (Personal opinion only!)

Another vote for Lancaster! My nieces went to the excellent grammar there and you’ve easy access to the Lakes, coast and Trough of Boland without being ‘too touristy’. The university seems nice too.

Very quick trains to Glasgow and London.

thanks @EmBeEmBe. not sure what post covid working world will be like but my dilemma is it's not worthwhile commuting from places like farnham or sussex daily to London city. DH & I are both FT but not high earners so it doesnt justify that sort of commute and transport cost (and tiredness and anciliary childcare cost without any family)

i am in a London zone 5 neighbourhood which has very easy access to countryside but secondary school option is very limited - i'm not sure my DC are grammar material and personally not a fan. My local comp is bad - below national standards level - the sort even I couldn't attend let alone allow DC to attend. In all likelihood i'll probably move somewhere else in London within a school catchment or downsize to go private.

my brother lives in York - 30 minute walk to the city centre, and his family is very happy there. Also all the other parents there seem really nice and grounded.

How about Winchester?