Crab,
As usual....a question for you is how do you know what was said...not said...and if the guy driving initiated the turn incorrectly....how was the crew in the back supposed to prevent that? Rotor Blade Clearance was not an issue.
Does/Did your cabin crew tell you how to drive your Sea King?
I can imagine Jones in the cabin did not ever tell you when to move your Tail Rotor Yaw Control Pedals and at some point assumed you bright enough to know when to do so while taxiing on a heliport....and you would not have been too happy had he done so.
I can see this as being a simple case of a handling error that was avoidable but some complacency crept into the mix as the aircraft was on an open Heliport Operating Area and the guy driving lost situational awareness and made a move that was not anticipated by anyone other then himself.
Put a stop watch to the video and time the interval from the first signs of the aircraft turning to the impact....how long did the crewman have to recognize a problem, and warn the Pilot? I don't think there time enough for anyone to have stopped the unsafe act once that pedal movement began and contact with the barrier.