a friend of mine witnessed an incident whilst driving home a female driver was driving erratically and dangerously
both parties were giving each other rude hand gestures and started to overtake on a roundabout and nearly had an accident with an oncoming car whos driver flashed his lights and also made some rude hand gestures
my friend took a video of the whole incident on his fone and when he was at home later that night the police paid him a visit and told him that he had been reported for the rude hand gestures he made to the female driver
he told the police the story of what actually happened and showed them the video he made
the police asked for a copy of the video and went off to pay the female driver a visit with the video with the view to prosecute
so in my mind yes the police would be very interested in onboard camera evidence
also if you go to youtube there was a video put on youtube where a motorbike rider videoed himself speeding and he was charged
If it's really dangerous then probably, if it's just someone cutting you up a bit at a roundabout then probably not.
I don't think your material would be admissable unless you backed it up so you'd probably have to give evidence if it were challenged if you're not willing to do that or if they think you're not then I guess they're unlikely to take it further