100,000 BC - S1-E1
Trivia: Many early (Hartnell-era) Doctor Who stories are known by more than one title. The first ever story is known as "100,000 B.C." When it was commissioned in October 1963, the story was called "Doctor Who and the Tribe of Gum." This story is also widely known by the title "An Unearthly Child", and this is the title under which it has been released on video and DVD.
100,000 BC - S1-E1
Trivia: It is a popular myth that the first ever Doctor Who story (broadcast on 23 November 1963) was delayed by 10 minutes due to news of the assassination of US President John F Kennedy the day before. This is not the case: the first ever episode of Doctor Who WAS delayed, but only by some eighty seconds, due to the previous programme (Grandstand) overrunning. The source of the myth seems to have originated from the fact that, due to power cuts blacking out several TV transmitters, the first ever episode of Doctor Who ("An Unearthly Child") was repeated a week later (30 November 1963), immediately before the first ever broadcast of Part 2 ("The Cave of Skulls").
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