Flying a drone anywhere in East Anglia will put you in very close proximity to one airbase or another.... it's a small area with a lot of military infrastructure. I've flown in Temple Bruer to shoot a Templar preceptory tower and had to register the flight with RAF ATC beforehand. Odds-on that this is just the media blowing the ordinary into the extraordinary.
Addendum.
If a few drones popping up in East Anglia makes for a good 'inherent threat' news story in November... They're going to go hysterical on the 25th of December... remember the 80's song "99 red balloons"?