I'm not sure flashing your lights, sounding your horn or sitting a quarter of a second off their bumper is recommended driving, either. I'm not defending the Astra driver's decision to brake-test you, but believe it or not, they were actually overtaking people in this clip, and without further footage, there's nothing to prove they were lane hogging except for your word.
Take a deep breath and keep your distance, before somebody does exactly the same thing to you again.
My Wife remembered this better than me, and reminded me of this idiot, I did not undertake on the slip road, he went to overtake me, and stayed alongside, he did not pull past and then when he joined he gave me no room to join I had to jam on my brakes to stop from hitting him
The sliproad is for joining traffic to build up to speed to merge with traffic on the motorway, if you sit in the offside lane going too slow, then you are causing an obstruction, that has to be avoided
Would it not have been more useful to take a photograph further back so we could see how close to your car he was parked? From that photo, it looks like he is parked within the parking bay lines. A zoomed in photograph of a car's reg plate doesn't really show much at all.
I'm not sure flashing your lights, sounding your horn or sitting a quarter of a second off their bumper is recommended driving, either. I'm not defending the Astra driver's decision to brake-test you, but believe it or not, they were actually overtaking people in this clip, and without further footage, there's nothing to prove they were lane hogging except for your word.
Take a deep breath and keep your distance, before somebody does exactly the same thing to you again.