Trevor, when I had the priv to do shifts on the Wilts (and, briefly, Sussex) aircraft we were obliged to observe several other caveats - for example, from memory, the minimum LS dimensions were double those for day ops at 4 X the max dimensions of the heli. About 3 years ago a change of 'ownership' of the PAOM Pt 2 meant that night HEMS could only be carried out within Wiltshire's boundaries.
Good though the kit was, I find it difficult to believe that even now NVG ops are considered 'unusual' in UK civvy life, rather than the norm as they have been in the military for so long. The Wiltshire line-check into an area near a rural car-park in the middle of nowhere was definitely one of the more memorable events (for all the right reasons).