Randall and Hopkirk (Deceased) (1969)

Season 1: Episode 15

A man enters Jeannie's life pretending that he is Marty returned from the dead. As he gradually builds Jeannie's trust with his alarming knowledge of Marty's life, Jeff, suspicious from the beginning finds that he is a runaway member of a gang and has taken Jeannie to the Cotswolds where she and Marty had their honeymoon to dig up something of the past.