Remembrance of the Daleks - S25-E1
Factual error: The events depicted are supposed to have taken place at the time of the broadcast of the first Doctor Who story... Saturday 23rd November 1963 at 5:15pm. However, the non-wintry weather and the bright evenings don't fit late November/early December.
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