Can't help but wonder what you were doing riding in the bus lane in the first place.
Granted, I don't know the road you describe, but maybe if you'd been behind this chap instead of, presumably filtering/undertaking on his inside in the bus lane, then when he pulled over without looking you would have been out of danger?
Some bus lanes are time based, i.e. a lane anyone can use during certain times. Not sure how the bus lanes work in London, but I think they are also timed, or bikes can go in them anyway?