Away From it All by Judy Astley
Alice has a scrupulously organised, comfortable life in West London with Noel - her second husband whose main ambition in life is to sharpen his golf handicap in time for retirement. But when her mother Jocelyn, residing in shabby splendour in a crumbling house on a clifftop in Cornwall, becomes ill, Alice and the family goes to look after her.
What she finds there appals her: her glorious childhood home falling into decay. Noel, helpfully, thinks Jocelyn should offload the house ('She's sitting on a goldmine, you know') and move into sensible sheltered accommodation. But their children love the freedom and beauty that they discover in Cornwall, and Alice begins to wonder whether her chosen way of life is necessarily the right one . . .
Good secondhand condition, paperback.