Diana Walker wrote children’s books, amongst which are these two horse books. Mother Wants a Horse is the sequel to Year of the Horse.
Finding the books: neither title was published in the UK, and both are easily available in the US.
Year of the Horse Abelard-Schuman, New York, 1975, cover art Barbara McGee
Harper & Row, New York, 1979, cover art Fran Stiles
Joanna’s brothers take care of a horse while his owner is in hospital. Joanna is not particularly interested in the horse until she sees John on his horse, which makes her think that maybe horses aren’t such a bad thing.
Mother Wants a Horse
Crowell, New York, 1978, cover art Andrew Rhodes
Joanna is unable to ride in the Royal Horse Show after she has an accident. After meeting two little girls whose mother wants a horse, she finds her times is taken up.