Never mind Northolt.
Is BZZ up to civil standards? In my time there, there were plenty of civil airliners and freighters using it. Probably under military contract, but does that in itself make it a military flight in the eyes of the court?
I remember the old trooping flights from Luton on Britannia (airline, not aircraft!). RR flight code, so in theory a military flight. But I would think that even if it was a military-classified flight, the courts would make mincemeat of the case if the actual operator was a civvy airline using civvy airliners.