Season 3 BBC One , 1973 Season 4 BBC One , 1974 - 1975 Season 7 BBC One , 1977 Season 9 BBC One , 1979 Season 11 BBC One , 1981 Season 1971 BBC One , 1971 Season 1972 BBC One , 1972 Season 1976 BBC One , 1976 Season 1979 BBC One , 1979 Season 1980 BBC One , 1980