What more can be said; a perfect advert in favor of some kind of road competency test for cyclists.
For me, the indication of the car is a secondary issue here - the indication could have come later or not at all depending on the diligence of the driver; it was general position which was wrong. Simply put you should have taken primary the moment you joined moving traffic in an overtake stream. My personal feeling is that you should be "in the wheel" of a car (blind spot, rear quarter, whatever you want to call it) in the magnitude of 1 or 2 seconds or less than 10 meters - anymore and you are "lost" to the car in front and surrender your escape opportunities. This essentially means filter stationary traffic, or filter slow moving traffic when you know you can clear the hazard zone almost instantly. Dithering around back there is reckless and needless; if the traffic is moving at roughly the same speed as you or you cant clear a car length properly, tuck in and join the queue. Everyone knows where you are then.
Take it on the chin OP. Cycling like this is a simple case of PP; Position (of yourself and everything around you), and Potential (what permutations can happen for whats around you). Not Probability as the problem with that is that sooner or later probability will turn against you, no matter the odds.
It isn't about what a driver has done wrong or what infractions of the highway code you can pin on his number plate, its about your skill as a cyclist to read a perpetually evolving scenario and adapt accordingly. As someone else eluded to it doesn't matter how many rules of the road they've impinged when you're in a box.
And I apologize if that is a tinsiest bit harsh or condescending, but after seeing someone almost lose their face tonight because they filtered a traffic stream which itself was moving at a steady 15-20 mph - just because it was on a down hill and its possible to do 25 down there - inside the door zone and with adjoining junctions blinded by on-road-parking, I'm seriously thinking a cycling proficiency scheme needs to be strongly considered.