One of the locations used for shooting in Amsterdam was Prinsengracht, the street that housed the Achterhuis, the attic where Anne Frank and her family hid from the Nazis, 1942-1944.
Third appearance of The Doctor's mentor, Borusa. Borusa is President of the Council of Time Lords. In "The Ribos Operation", Romana told The Doctor that Borusa became President, following the events of the previous story "The Invasion of Time".
Second guest role for Michael Gough. 17 years earlier, Gough played The Toymaker in 1966's "The Celestial Toymaker" opposite William Hartnell as The First Doctor.
Ian Collier was cast because it was felt he looked like Peter Davison, which is irrelevant because his face was always hidden beneath a mask.