At one point, it appeared Blake might be written out in this episode, with Grant being introduced as a potential replacement.
In the original script, the cyber-surgeon was called Doc Holliday, which changed to Doc Holli and in the final script it became Docholli.
Neither Zen nor Orac appears in this episode, although Orac is mentioned, making it the only episode after Space Fall (1978) for which Peter Tuddenham was not required.