Please report dangerous drivers to the police - Roadsafe. Report to plod, not just whinge here.

Nice letter, Tom...
+1
I wrote a similar letter to a coach company last year, including: "I consider this driver's behaviour to be unprofessional and unacceptable. I would be interested to know what training, reporting and monitoring procedures your company has in place to ensure the safety of other road users."

I got the sort of reply we want: "As you would expect we take reports of dangerous very seriously. My colleagues within the Quality Department, who are qualified PCV Instructors, have identified the driver concerned. Under these circumstances they hold an interview with the driver regarding the incident and their normal procedures then include a driving reassessment, silent checking and re-training as well as disciplinary action when warranted."

If you get a dismissive or hostile response then you should report the company further, either through the Police RoadSafe site or to the Traffic Commisssioners.