Entered a 20mph speed limit, due to my black box, the van driver behind didn’t like the speed at which I was going. Instead of overtaking he continuously flashed me and left on his full beams for a 5 minute drive, following me home, across several roundabouts and turn ins. I then pulled over before arriving at my house where he pulled alongside me and asked “do you want to say anything mate”, in which I replied no, do you? He said I’ve got you all on my camera, I said likewise, it was a 20mph limit, then he sped off out of the estate.