The other aspect worth a reminder is the operation of the aircraft under a Permit rather than a C of A. As the AAIB report points out, carriage of the passengers who were in the aircraft was outside the terms of the permit. I would think that the insurance company concerned will be able to wiggle out completely from any payout.
I have often wondered whether the people who fly in Permit helicopters are aware of the limitations. I suspect frequently not. It is all fine until some terrible incident like this happens.