It's in Sutton. Aka Slutton. Yeah my first thought was that if they got hit the ka would have been dragged into me. Well I edited the video to ensure that it ended with me right behind the ka so the plate was fully recognisable. I wonder if it might get back to them eventually.
Don't brake test. The correct thing is to leave a big gap between yourself and the car in front by taking your foot off the accelerator so they have to slow down too. Otherwise they can screw you for braking with no cause. Even if you are being tail gated.