Midnight is a Lonely Place/House of Echoes by Barbara Erskine

MIDNIGHT IS A LONELY PLACE - After a broken love affair, biographer Kate Kennedy retires to a remote cottage on the wild Essex coast to work on her niew book until her landlord's daughter uncovers a Roman site nearby and long-buried passions are unleashed.
HOUSE OF ECHOES - When Joss Grant, adopted at birth, inherits a beautiful old house on the East Anglian coast, it is a dream come true. Eager to begin a new life there with her husband and son, she is also impatient to find out abour her newly discovered family who lived there for generations.