Revelation of the Daleks - S22-E6
Visible crew/equipment: In the first scene of episode 2 you can see a member of the crew casually walking in the background.
Revelation of the Daleks - S22-E6
Plot hole: The DJ fires the ultrasonic gun, to demonstrate it to Peri. The glass in the doors breaks. When The Daleks arrive the glass in the doors is unbroken. It then doesn't break the glass in the doors in any of the other times he fires the weapon.
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