Addison Lee is a good alternative. Drivers tend to be a bit more professional, prices are not that much higher and cars are generally nice.
http://road.cc/content/news/56999-addison-lee-chairman-airs-...
The Keen Group have always been reliable for us (but could hold similar views for all I know)
(FWIW I'm both and sometimes ride a motorbike or drive a van.)
I have also seen bikes blast through pedestrian refuges during the rush hour
Oh, and don't complain that infrastructure built for cars sucks when used by bikes.