Film them. Then send the company the link to the video. Trust me, if this is true then they certainly would not like the image their employees (or managing directors even), portray. And you have every right to do this.
Nearly clipped me when overtaking me at an insanely high speed in the rain. Also, the license plate was on a black Ford Kuga, not a grey Citroen C3 like the MOT states...
This driver tugged me off