Here it is.
Summarised, in part, as:
Despite extensive analysis of the limited evidence available, it was not possible to determine why both fuel transfer pumps in the main tank remained off during the latter part of the
flight, why the helicopter did not land within the time specified following activation of the
low fuel warnings and why a MAYDAY call was not received from the pilot.
Also, it was not possible to establish why a more successful autorotation and landing was not achieved, albeit in particularly demanding circumstances.