Factual error: An egotistical, prissy and dishonest lawyer like Mr. Fletcher wouldn't make the mistake of allowing his name to be misspelled on his office door. It reads "Winfred Fletcher." His first name, as it's pronounced throughout the episode, is "Winford."
Plot hole: Well within earshot of the others in the small room, Curry comments to Heyes (purely for the viewers' benefit, since Heyes already knows it) that if Lom Trevors is killed, their amnesty will go with him. This information should have blown their cover, but for some strange (and unbelievable) reason, no one wonders what he's talking about.
Audio problem: Final sound edits were incomplete on this episode when star Pete Duel committed suicide, so his dialogue is "looped" by another actor in several places. Though it's an excellent imitation, it is most noticeably not Duel's voice when Heyes and Curry are waiting for Harry in the opening scene, at the campfire with the Tapscotts, and when Harry tells them about the trial's outcome.
Continuity mistake: Blake spies on Heyes, Curry and Louise as they sit together on the picnic blanket. But in the view through his telescopic gunsight, Louise is missing. When the shot returns to the camera's normal POV, she's sitting right between Heyes and Curry, where Blake's sight couldn't possibly have missed her.
Visible crew/equipment: After the street brawl, Heyes, Curry and Stokely walk away arm-in-arm and pass a man in a 20th Century short-sleeved blue shirt with a very 20th Century haircut, leaning on a piece of equipment to the right of the screen - apparently one of the film crew.
Revealing mistake: The outlaws all have their hands tied behind their backs. But the one wearing glasses, apparently unaware that he's in the shot, brings both hands up to push the slipping glasses back up on his nose, then quickly puts his hands behind his back again.
Visible crew/equipment: When Heyes and Curry leave the saloon and walk across the street, a microphone mounted on the camera rigging pops up into the shot at the bottom of the frame and follows along beside them. (This is visible in the US aired and vhs versions, but was edited out of both the BBC version and the recent dvd release.)