Robert Goddard: Painting the Darkness (UK 1990)
From the Publisher:
The stranger announces himself as James Norton, but claims he is in reality Sir James Davenall, the man to whom Trenchard's wife Constance had been engaged, and who had committed suicide eleven years ago. Sir Hugo, James's younger brother, and his mother, Lady Catherine, refuse to recognise Norton and force Trenchard - who fears the loss of his wife's affections - into an uneasy alliance against him. But Trenchard must plumb the depths of his own despair before the dark secrets of the Davenall family can finally, shockingly, be revealed.
Robert Goddard: Painting the Darkness. Corgi Books, ISBN: 0552132829 (May, 1990), 602 p., £4.99 / £7.99