Weird!!!!!!

Very doubtful that it would be anything to do with wi-fi, or even the powerline connection to the net. There is a chance, I suppose, that the built-in FreeView tuner may have been feeding some sort of signal to give the audio you were hearing, which presumably ceased when the condenser that was holding/supplying the power ran out of juice.

I would say that even that though is the remotest of possibilities so you may never get to the bottom of it. Keep an ear on the TV for a wee while and see if it recurs; if not, then it will remain a mystery

 

Thanks, FC , but I think I prefer clueless' explanation.

@clueless1 It could be that they're annoyed because I've now blocked off the chimney! Although I've heard rumours that Santa is now using drones