It was working at 6:34am today. Didn't work again after that. No idea if there's a certain quieter period when it functions briefly, and once people start flying, it grinds to a halt?

Added: Tried at 8:40pm on the 8th and all fine again.
Do need to further experiment to see if there are specific times. If I can't fly anywhere at that time, it may work. Times when flights are leaving say LHR, it fails.