So, if I had been in the vicinity of this incident, or possibly on-board, I could tell you the ASU's explanation of the TRA. It was, they said, a noise issue, to prevent disturbance to those working within the TRA. Strange then that the only heli operating within the TRA was the ASU's noisy machine, flying considerably lower than any other aircraft, and directly over what would have been the centre of the TRA if the coordinates had been correctly published.
They also burnt up a good chunk of tax-payers money whilst sitting rotors running on the ground for nearly 25 minutes.