Race tells Jonny that sargasso is the Portuguese word for grapes; it isn't. Portuguese sailors named the Sargassum seaweed after the wooly rock rose, a plant that grows in Portugal.
Hadji does not appear in the first episode The Mystery of the Lizard Men (1964) (18 September 1964). He appears in all other episodes, but is introduced as a new character in episode 1.7 Calcutta Adventure (1964) (30 October 1964). "Calcutta Adventure" was actually the second episode produced; the episodes were shown out of production order.