Trogs,
I agree that it could be construed as an overkill, but if the oil companies are willing to invest the sorts of sums necessary for 2 large, expensive new helicopters to do SAR here, they will have to do night training anyway and part of the cost of running the night part of the SAR could be offset by finishing all present night SAR contracts, which I'd guess are for a total of around 6 or 7 helicopters, plus extra associated crews between Bristow and Aero right now.