From the beginning I have suspected that this was a case of "hivizziness".
There may well have been one drone at the beginning, but possibly not.
But everything after that was probably "I thought I saw...", lights on lampposts, reflections of airport/distant helicopter lights, etc. and apparently Police Drones.
But the police are paranoid of being blamed if there is an accident, i.e. they ascribe value on that side, but no value to the disruption caused by closing the airport.
Some of the responsibility for this lies with the way that the media would react if there was a crash.
But the deliberate misinformation such as "industrial specification", "numerous illegal drone sightings" is disgraceful.
It recalls the way that immediately after the shooting of the innocent Jean Charles de Menezes the police PR department put out false stories that he had jumped the Tube barrier, run away from the police, and was wearing a padded jacket in the summer.
Policing is not easy, but they should do better at:
a) recognising that they are just are prey to groupthink delusion as other people
b) admitting mistakes quicker.