Shy
I think it's most likely to have been someone messing about with a R/C model, despite what the modelling experts said in the report. Not too long ago I reported a R/C model aeroplane inside the London Heathrow control zone as it went past me at 1500 feet. I understand that R/C models should not officially be flown above 400 feet above ground but models are easily capable of flying much higher; the model flyer has no means of gauging height.
I have read it - I'm not saying a model could be not flown at that height, just that it couldn't be done with any degree of accuracy in the dark.
Nige