Diplomacy doesnt always work mate. People in their cars can be very agressive even if they are totaly in the wrong. I drive a bloody big bus all day and obey the highway code like rules from god but i still get verbul abbuse on an almost daily basis because the standard of driving by some is so bad. You cant reason with them even if you calmley explain what they have done wrong they wont listen to you. I quit often feel like getting out and bashing their heads against a wall, but you do have to show some restraint actually pushing them about takes you down to their level. Just say prick and move on is best.