 On @-@ screen chemistry with existing players determined the later changes to the cast . Brian Wilde , Michael Aldridge and Frank Thornton each brought a sense of completion to the trio after the departure of the preceding third man . Tom Owen provided a direct link between his father and himself after the death of Bill Owen . Keith Clifford was added following three popular guest appearances on the show . Brian Murphy was chosen as Nora Batty 's neighbour because of his work on George and Mildred , where he played the hen @-@ pecked husband to a strong @-@ willed woman . 
