From Wikipedia (emphasis mine): The Chimneys of Green Knowe was a commended runner up for the 1958 Carnegie Medal.
In the United States it was published within the calendar year by Harcourt, entitled The Treasure of Green Knowe.

The Chimneys also features Tolly, who has returned to Green Knowe for the Easter holidays. As she mends a patchwork quilt, Mrs. Oldknow continues telling Tolly stories about the previous inhabitants of the house. This time, her stories concern Susan Oldknow, a blind girl who lived at Green Knowe during the English Regency, and the close bond of friendship that developed between her and a young black page, Jacob, brought back from the West Indies by Susan's father, Captain Oldknowe. The plot also concerns the whereabouts of the jewels of Maria Oldknowe, which may or may not have been stolen by the unscrupulous butler Caxton.