I fucking hate those guys, the best thing you can do is just make their lives a nightmare and drive safely, I constantly get tailgated in my town for driving the limit and just laugh at them when they start trying to flash their lights etc.
I haven't had near misses because I'm so careful I guess, but then again, I have to deal with people like that on a daily basis in my town because it's a shit hole with loads of chavs that have Audis and BMW's.
Since it's legal, I am seriously considering getting a tank and seeing what they try then, I might slam the breaks and see what happens lol
the thing is it's a game of chicken and they're counting on you to do exactly what you did and swerve out of the way and put yourself at risk, best thing you can do is piss them off so they go and crash into a lamp post or something.