jacqueline hill, who played the first doctor's companion barbara wright, makes a guest appearance as lexa, marking the first time a companion has returned to play a role other than their original character. brotadac is an anagram of "bad actor", an in-joke by the production team. bill fraser only agreed to take the role of grugger on condition the character was allowed to kick k9. his request was granted; he later appeared in the spin-off pilot "k-9 and company".