Randall and Hopkirk (Deceased) (1969)

S1E15 The Man from Nowhere

A mysterious man steps into Jeannie's world, claiming to be Marty back from the grave. As he earns her confidence through unsettling insights about Marty's life, Jeff, who has been wary from the start, uncovers the truth. The man is actually a fugitive from a gang, and he has lured Jeannie to the Cotswolds—the same place where she and Marty spent their honeymoon—in search of buried secrets from the past.