Rumer Godden was a prolific writer and, among other stories, created the eternal classic 'The Story of Holly & Ivy'.
This didn't really match that in terms of emotional impact and originality. Our heroine is Tibby, a 7 year old girl, who comes with her mother to live in a grand old house called Pomeroy Place. Her mother, Mrs. Winters, is the housekeeper, cook, and maid-of-all-work in a house that once had an army of servants. There is Jed who does all of the gardening and once looked after the horses when elderly Miss Pomeroy still had them.
Tibby is alone most of the time and falls in love with the old day nursery. She especially loves the large wooden rocking horse. That rocking horse has a secret, and the reader must muddle through a whole book before the seven year old realizes that secrets are silly things.