The King of Knaves Affair - S1-E13
Factual error: Supposedly engraved on a ceremonial sword is the wrong date - 1443 - for the fall of Constantinople. That happened in 1453. (00:33:15)
Factual error: An edition of the 'Melbourne Herald' newspaper can be seen in this episode, and appears to be dated Friday, December 24, 1964. Yet 'Thunderbirds' is supposed to be set in the 21st Century (2026 or 2065, depending on who you believe). This date is also seen on newspapers which appear in the episodes 'Edge of Impact', 'The Impostors' and 'Cry Wolf'. Also, to compound the error, December 24th, 1964 was actually a Thursday, not a Friday.
Factual error: Semi-automatic pistols, rifles and fully-automatic rifles and machine guns never eject spent shell casings in the show.