I, unfortunately, have to drive in central London on ocassion and it's a nightmare with many cyclists. I cycle commute most days and drive rarely.
The problem is not managing around various cycling styles. Vehicles should bear the repsonsibility of making sure their manouvers are safe from cyclists who may be in primary, secondary, filtering etc etc.
However, what I find difficult if sometimes havng to deal with cyclists riding badly. I have had to make emergency manouvers to avoid cyclists rlj, swerving across lanes without looking, jumping off pavements infront of me. Any of these would not be seen as my fault in most circumstances, but I would hate to be the one to injure someone's son/daughter/wife/husband etc etc etc. I can easily see how a driver who drives all day would find this extrmely difficult and would really get annoyed with some cyclists. I only drive around once a month in/out of London, but I see enough to know that it would be a problem.
Education is need on all sides.