Caterham on the Hill has an excellent community spirit, a festival in the summer, fireworks display, carnival, street party, friendly pub, village hall, pilates, ice cream shops, coffee shops, butcher hanging in there. Not quite pretty and chi chi yet but going in that direction. A nice primary school to volunteer at, 2 or 3 others nearby. There's also the Westway Centre which is a drop in centre for older folks and lots of yoga and volunteering opportunities there. Maybe not quite rural enough for you but id give it a look. Excellent dog walking and green spaces at Happy Valley, Farthing Downs and the Aerodrome, Caterham Viewpoint as I said in a pp.
Caterham on the Hill is about the same size as Warlingham Green and easily walkable to all of the above if you live on the Hill rather than Caterham Valley. Its also strangely flat for being on top of a hill 😀 (couple of roads flood though due to an underground stream so be aware of that if looking at houses). You would easily meet people via the friendly pub and there are also very active Rotary, Roundtable, U3age etc groups. Knitting circles, book clubs etc. I live there and really like it, as you can probably tell 😃.
I do go to Warlingham as have friends there, solicitors is there, the particularly nice ice cream shop is there 😀 (though Caterham on the Hill also have 2), I use Sainsburys for the foreign exchange counter and go to Knights Garden Centre, but I feel like there is more community spirit in Caterham (though maybe im just not aware of it in Warlingham).
Why did you discount Oxted again? I also really like it there (and its probably a bit closer for the drive to E Dulwich).