The Silver Brumby by Elyne Mitchell. Click here to read an extract.
It took me about a year searching after reading this in school to find the same copy I remembered. The red version.
If your after any kind of old book you must make a trip to The Cottage Book Shop, Elm Road, Penn, Bucks, HP10 8LB. (opening hours: Tues – Sat. 10.00-1.00 2.15-5.00)
Its kind of like a library but without the fines, books range from 10p to about £5 (I rarely see any for more than £3). I go there once every few months and return the books I’ve read so other people can enjoy them too. Its amazing. Tiny old cottage, piled floor to ceiling with books from very old to very new.
Don’t think they will take all your books though, they are surprisingly selective