I am a HGV artic driver of 5 years experience and I cycle mainly offroad.
I have never driven in Central London, which is a different kettle of fish compared to anywhere else.
In my opinion, the driver should have backed off a little - look at his proximity to the cycle AHEAD of the guy who was hit. He was a bit close.
This shows intent to "get on with it". Why? Not necessarily to teach anyone a lesson. Perhaps he was unladen and wanted to finish for the day, maybe he had another job to do, who knows.
Key point - 'mickle' is convinced the driver was aware of the hit cyclist before the impact. I doubt this. I believe that the artics proximity to the cyclist ahead of that guy, indicates that in the DRIVER'S MIND, *that* was the closest cyclist to the artic unit. A human on a bicycle colliding with the passenger door would likely make a driver aware that something has happened.
The drivers angry reaction - most would react like that. It is a confrontation. He is defending himself, possibly feels threatened/scared, but also feels the situation is not of his making. He doesn't seem aggressive to me in the circumstances.
The cyclist is mostly to blame, in that situation with 6+ cyclists, you have to watch your nearside mirror like a hawk, even if it means not paying as much attention to what is ahead of you.
Ultimately haulage companies should expect deliveries/collections in Central London to take a long time, allow for that and not pressure drivers. Drivers should also be pragmatic about making progress through these junctions.