Flora later met the Eighth Doctor and tried to kill him, thinking it would stop Isaac's composition from destroying more of the universe. After learning that the Doctor could prevent Isaac's music from being created altogether, she travelled with the Doctor to the fishing shop where Isaac first met the Doctor. Flora took Isaac's place on the Sixth Doctor's fishing trip instead and became his companion. (PROSE: DS Al Fine)
The Sixth Doctor's companions from stage plays are difficult to assert with certainty, as different actors played the Doctor in the same play. If a medium is not mentioned, then this incarnation did not have companions who were original to that medium; it does not mean that this Doctor failed to appear in that medium.