Guest Stars Olivia Grant as Helen Cartwright Mark Bazeley as Dr. Bill Prentice Jonathan Hyde as Sir Edmund Sloan Luke Allen-Gale as Derek Clark Fiona Ryan as Margaret Bell Sophie Stuckey as Pamela Walters Albert Welling as Wallace Clark Billy Geraghty as Gas Man 'Watkins' John Flanagan as Mr. Greaves Jonathan Guy Lewis as Rev Monkford Alan Morrissey as Denis Bradley Dominic Taylor as Dr. Frank Cartwright Will Richards as Brian Powell Uncredited Colin Dexter as Don Dining at Hall