Report it, might help someone elses case if they kill the little scotes and they've already been reported for a similar incident.

Bit like that story in the paper a while ago: Two blokes get into road rage argument on m-way. Pull onto hard shoulder, one gets punched and cracks his head on the deck and dies. Dead bloke had been reported for another road rage incident a week earlier. Helped the accused get a bit of sympathy.