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: 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: In an early TARDIS scene, at one point the cable powering the console is seen running from the base and under the wall.
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.
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