That signs points to the Deanery Book Stall, The Prior's Hall, Winchester, where I had a pleasant browse earlier in the week and bought a copy of The Ladies of Lyndon by Margaret Kennedy, acting on Thomas's recommendation from a year ago.
"Agatha is the most beautiful, the most desirable of debutantes, a young woman reared for one purpose only: to make a triumphant marriage. This she does, and becomes Lady Clewer, Mistress of Lyndon, a perfect country house set in rolling Oxfordshire parkland. Head of a vast household, reigning over a large and idiosyncratic family - brilliantly portrayed - her days are filled with games of croquet, afternoon tea, witty conversation: Edwardian life at its most perfect. But Agatha is haunted by the the memory of a first attachment to her cousin Gerald - and the marriage contract at Lyndon includes no clause permitting passionate love ..."
Have you read it, or Margaret Kennedy's more famous The Constant Nymph (a copy of which I left on the shelf)? Nicola Beauman says in her introduction that it is "extraordinarily rich in theme and subtle in overtone" and "more moving and less sentimental" than the later book; "a work of fiction of a high order."