Has she read Siobhan Dowd? London eye mystery too young but the other two not.
What about some funny books? The Gerald Durrells? Agree Wodehouse.
Horses, too young but I still enjoy them, my friend Flicka, which she would read with a more adult eye, green grass if Wyoming. Animals, the longest journey?
Classics, Sherlock Holmes stories, The Woodlanders, a day in the life if Ivan Denisovic, the checkov short stories, Gorky's childhood and apprenticeships.
Agree Gardam and Dodie Smith.
Garner the owl service? Is the dark is rising sequence too young?
if she likes Anne, try Emily of New moon and also Rebecca of Sunnybrook Farm. Also the more adult of Frances Hodgson Burnett.
A room with a view.
Biographies a great stand by. Also diaries. The sequels to when Hitler stole pink rabbit?
What about poetry? Wendy Cope appeals a lot to that age (and me).
Cold Comfort Farm.