Revealing mistake: At the point where someone gets a small bruise on the upper arm, the crew are all in a pile and thrashing about on the floor. There are 5 pairs of legs instead of 4. Arthur is in his pajamas, Zaphod is in orange trousers, Trillion is lying on top of Ford and Ford is too far away for them to be his legs. [The fifth pair of legs belong to the person playing zaphod's third arm - doesn't mean it's not a mistake, but that's where they come from.]
Visible crew/equipment: While Ralph and Pam are watching the mustangs Ralph starts taking pictures, then when Pam points to the black stallion, in the first shot of that beautiful stallion the animal trainer can be seen hiding behind the bush. (00:02:40)
Tiptoe Through the Penfolds - S5-E3
Continuity mistake: Although Danger Mouse is supposed to be on his own, when he turns a corner in the car, in the overhead shot, you can see Penfold sat next to him.