Hallett (Terror of the Vervoids)

Hallett was an investigator assigned to investigate the grain shortages on Stella Stora. While on the Hyperion III under the name Grenville in 2986, he was recognised by Kimber, blowing his cover. He disguised himself as a Mogarian named Enzu, and took some demeter seeds from Professor Sarah Lasky's lab. He was later poisoned by Doland.

After his death, the Sixth Doctor claimed that he had met Hallett before. (TV: Terror of the Vervoids)