That's not the issue. He should have had a number plate to operate a quad on the public road, even one for agricultural use. I have some footage of him riding on the road. A helmet isn't required by law but number plates are. A week earlier I was at a local beauty spot when I saw a drone flying, a Mavic Pro, I went over and introduced myself to the pilot and showed him what an Anafi can do. This esteemed agriculturalist (does this forum allow you to say sheep-shagger?) was working nearby and my new acquaintance told me that he'd had a run-in with him, getting told to get off his land. As he wasn't on his land he had continued flying. As a result it wasn't a complete surprise when this chap turned up just as I was about to pack up and move on anyway.
He very nearly but not quite threatened to shoot my drone. It would give me tremendous pleasure to report such a threat to the police as this would likely result in him being stripped of his the right to own firearms of any kind. If I see him again I will make a point of asking how exactly he proposes to get my drone.