I particularly love the Christmas scenes in this book.
"Mummy appeared from the sitting-room. "Bed,' she said. 'Go on, Rory, have a bath and mind you wash. Go on. Hurry up or Father Christmas won't come,' she threatened.
'Don't believe in him,' said Rory going upstairs backwards and as slowly as possible. 'I know it's only you and Dad.'
The rest of us were shooed to bed at ungodly hours with irritating threats about Father Christmas. And it was all nonsense because the parents always go to the Midnight Mass and do the stockings when they get back, and that wasn't likely to be much before a quarter to one."
The book's full of stuff like this; all acutely observed. It's the title of hers that I'd really love to see re-published.
You can read more about Josephine Pullein-Thompson here.
Read more about the pony book in Heroines on Horseback, my survey of the world of the pony book from the 1930s onwards. There's a whole, long, chapter about the Pullein-Thompsons, with biographical info, and analysis of their books. You can buy a signed copy from me (I'll post them worldwide). The book's also available from the usual sources, or your local bookshop.