I am wondering if there is something significant in the fact that the latest AAIB Bulletin makes a point of stating that of the final four tasks G-SPAO completed before the accident, the first was "non urgent", the second was "observation" and the last two were "non-urgent". I am baffled as to why, given such lack of necessity of these tasks, the fuel status was allowed to get so low. Surely any competent pilot has in his mind a background awareness of his endurance and generally monitors this, particularly as limits get closer? And at that time he double checks fuel quantity indications and is on heightened alert for any cautions or warnings. Furthermore if, due to any failures, fuel quantity indications, cautions and warnings didn't all add up, wouldn't you revert to original planned endurance as the reference?
I find it hard to believe running to such low reserves is routine for police helicopter ops, particularly when performing non-urgent tasks.
Of course it might be that the reason none of the above happened properly was also relevant to the reason an autorotation was apparently not entered into, when the (from quite predictable fuel exhaustion) double engine failure occurred.