These are minor human characters in the series who only appear once or only have very little information known about them.
Mr. StevenAn archaeologist who appeared in Racing Muck (Season 8).
Tony the HairdresserA hairdresser who only appeared in Wendy's Big Night Out (Season 8).
Mr. CostelloA drive-in movie manager who only appeared in Trix and the Bug (Season 9).
Dickie Oliver is a character introduced in Ready, Steady, Build!.