Spring Magic by D.E. Stevenson

Frances Field knows she was lucky to be taken in by an uncle and aunt when she was orphaned at three but whatever she owes them has been amply repaid – she has acted as housekeeper and slaved for her indolent aunt since her late teens, without payment or time off. When the war begins she is eager to do her bit but is forced to go on catering to her aunt’s every demand until a bomb lands near their home, breaking most of the windows in Wintringham Square.