Report to Police (as well as bus co)
I had an incident with a Newport Bus in Cardiff a few years back. Driver was gesticulating and shouting at me to get off the road, and then pulled in on me.
Took advice from a friend in the Police who suggested that it ammounted to both assualt and dangerous driving - although unless other witnesses came forward (ie passnegers) was unlikely to proceed to prosecution due to my word against his. However, PC friend did advise that even with insufficient evidence driver would get a formal talking to, as a PSV driver he should be demonstrating public responsibility etc.
As posted above - too many (any?) warnings = possible retraining / disciplinary / career implications.
To my ongoing regret, I did the decent thing and complained only to the bus co...