Six of the guest stars also appeared in episodes of "Doctor Who": Brian Blessed, Nicholas Courtney, Roger Delgado, Nicolas Chagrin, Clive Cazes and Hans De Vries.
When Max introduces himself to Jeannie, Jeff and Clara he says his name is Maxwell House, which is of course a brand of instant coffee. Moments later Suzanne introduces herself as Suzanne Monet, which she makes sound like Cezanne Monet, the surnames of two Impressionist painters.