No Boats on Bannermere by Geoffrey Trease, for the 1949 Club

The Melburys – Bill, Susan, and their mother – have been living in a crowded London flat until Mrs. Melbury’s Cousin Fay dies and unexpectedly leaves her a cottage in Cumberland, in the Lake District. There’s a catch: they must live there for five years running or it will be sold and Fay’s son would get the proceeds. Bill has just made his school’s second team (Rugby? Cricket?) but swallows his disappointment, and he and Susan encourage their mother to make the move, which happens quickly.