I was v scared by The Owl Service and I think I was about 20 when I read it! (The claws........)
Have just reread I Capture the Castle - it was out of print for years but was reissued as a Virago quite recently. Dodie Smith also wrote the Dalmatian books but they don't appeal in quite the same way, somehow.
The Painted Garden was about a film of the Secret Garden - Pauline and Posy were both in it - and what about A Little Princess! And Little Lord Fauntleroy!
The Kizzy book was called the Diddakoi (sp?) - I think it was Rumer Godden. She was very prolific - is she still alive?
The latest Anne Tyler is Back When we were grownups (or grownup), I haven't read that yet, am waiting for a book club offer! I have read many of hers and love them. I like Alsion Lurie too but she is not as witty or touching.
For all these writers who wrote so many books the library is a good bet, some of them are out of print but will still be available in libraries and they usually have a pretty good facility for finding things at other branches.
Another lovely writer is Philippa Pearce (Pierce?) - I esp liked A Dog So Small, though that made me cry too. And one of my daughters, between the ages of 9-ish to 11ish, devoured Charlotte's Web (more floods), The Trumpet of the Swan and Stuart Little, all by E B White (she named successive hamsters after the heroes)