Cast Credits Only Fools and Horses (1981) Guest starring as Grayson Episode 6x03: Chain Gang (Jan 22, 1989) Doctor Who (1963) Guest starring as Roth (2 episodes) Episode 12x10: The Sontaran Experiment, Part Two (Mar 1, 1975) Episode 12x09: The Sontaran Experiment, Part One (Feb 22, 1975)