Yes Mike, but whilst I agree entirely with all you say about the legality of the flight: the state of registration of the aircraft has no bearing whatever on what went wrong.
There are hundreds of UK based N reg aircraft operating quite safely and legally, equally I am quite sure that a good share of the illegal grey charter market is flown in G reg aircraft.
It’s the activity that needs to be stopped and you won’t stop it by forcing pilots to re-register all N reg aircraft.