The Rescue - S2-E3
Revealing mistake: At the beginning, as the Doctor is standing in the TARDIS door, the cave wall can be seen through the TARDIS.
Continuity mistake: When the Doctor and Ian encounter the Frankenstein monster in episode four, you can see a Dalek behind them, even though it's long before The Daleks arrive in this time zone.
The Dalek Invasion of Earth - S2-E2
Visible crew/equipment: Just before Dortman leaves to test out his bomb, he comes towards the camera. When he's doing this, look at the right side of the screen - you can see a crewmember's shadow. It can't be Barbara or Jenny because they then enter from the left.
The Romans - S2-E4
Factual error: The geographical references in this story are somewhat suspect. Assissium is the modern town of Assissi, some 70 miles north of Rome and the same distance east from the sea. The Great Fire of Rome took place in July 64AD.
Factual error: In episode one, Abraham Lincoln seems to have affected a southern accent and put on some weight.
Continuity mistake: In episode four, when the Doctor and Ian return to Frankenstein's lab, the monster is lying on the table in the opposite direction from when they left.
Deliberate mistake: In episode 3 of 'The Web Planet' (titled 'Escape To Danger') watch as one of the Zarbi operators, his vision impaired by the costume, runs right into the camera. So far behind schedule was the recording of this episode, however, that this mistake was retained in the finished episode, as there was no time left for a re-take.

Visible crew/equipment: (Episode 5) When Vicki is in the jungle she happens upon the TARDIS and bangs on the door begging to be let in. In the next shot we can see the boom pole/mic hovering in the background, then a hand appears which seems to guide the actress to head in that direction. (00:07:45)
Visible crew/equipment: In the scene where Ian's pen vanishes, as he checks to see if he is being followed you can see a boom mic shadow on his coat.
Visible crew/equipment: In episode four, when Ian and the Doctor descend the stairs into Frankenstein's lab, you can see a boom operator and mic behind Ian, at the left side of the screen.

Visible crew/equipment: Near the end of episode five as The Daleks plan their attack, a BBC camera can be seen in the background on the right. (00:21:20)
Visible crew/equipment: (Episode 5) After The Daleks plan to organize a full-scale search of the jungle at daybreak, when it cuts to The Doctor and Ian, the shadow of the boom mic moves around at the left side of the screen. (00:16:35)

Visible crew/equipment: (Episode 4) After Ian shudders from the apparition he continues to follow The Doctor down the hall, and the camera casts a shadow on Ian. Then, when The Doctor finds the stairs leading to the laboratory he tells Ian he must see what's on the table. Just as Ian states his displeasure at the thought, the boom mic (and its shadow) pops up into view at the bottom of the screen, in front of Ian. (00:05:15)
Visible crew/equipment: (Episode 6) At the very end, after Vicki and The Doctor have watched Barbara and Ian's return to 1965 on the Time-Space Visualiser, when Vicki hugs The Doctor the moving boom mic casts a shadow at the top, left of the screen. (00:24:30)

Revealing mistake: In episode 1 when the Doctor, Ian, Barbara, and Vicky leave the TARDIS, wheels are visible which move the prop around. There is also no back to the prop.
Revealing mistake: In episode 1 when the Doctor is checking the controls you can see the studio lights to the top left corner where the set doesn't completely connect.
Continuity mistake: Towards the end of episode 2 it's nighttime, but when Ian and the Doctor lure the Dalek over from the TARDIS, and when it falls, it's daylight.
Visible crew/equipment: At the beginning of episode two, the Doctor finds Ian unconscious with a very obvious shadow of the camera and cameraman looming over him.
Visible crew/equipment: At the end of episode 3, a venom grub starts chasing Ian. As it enters the screen however, you can see the actor under it crouching down.
Visible crew/equipment: In an early TARDIS scene, at one point the cable powering the console is seen running from the base and under the wall.
Answer: In 'The Five Doctors', three separate Cyberleaders are definitely used. So it's likely that Cyberleaders are like unit commanders, of which a fair-sized army might have several.
Daria Sigma