I recently had a bus come so close to me that it's step clipped my pedal. When I caught it up at the roundabout, the driver completely ignored me.
I sent a strong but courteous email to the bus company and was completely ignored, so have reported it to the police, who have confirmed that they are meeting with the company and driver.
This was before I had a helmet cam, and no witnesses.
Think I did the right thing. He probably didn't mean it aggressively, but if nothing else, he needs to be advised of how vulnerable cyclists are.
Same goes here. Even if you think it's not a major issue, a little education would probably help hugely, and it may save someone's life. See how the company respond, perhaps.