Traffic Incident Advice

Also if there's no injury or damage the cops don't care. Scaring the shit out of people with a few tonne of steel is quite ok.

this^^

unless you get the reg and a good descrip, and £££ damage was done, police will virtually hang up on you.
best thing is to just move on and don't dwell on it, you'll never see them again so why let it bother you?
next time get her to get the reg, or reap vigilante style revenge at the next set of lights*

*this will ensure more trouble than worth.