The Foreign Field: The Morland Dynasty, Book 31 by Cynthia Harrod-Eagles
It's 1917 and the Allies are determined to finally defeat a weakened Germany - everything is building up to the summer's Big Push. Germany strikes back with U-boat attacks to starve England out, giant aeroplanes to bomb London, and the cunning withdrawal to the Hindenberg Line. Every Briton must do his bit, and the Morlands are involved at every stage: fighting and nursing in France, stoically surviving at home - and finding love where they can along the way.
Continuing the great saga of the Morland dynasty, The Foreign Field carries its members into a new set of conflicts and tests their courage to the limit.