I met the same (presumably) NH90 on Sunday early afternoon when I was out for a run up to Tunnel Gully and back. They spent time over the Remutaka incline, then low hovering over the Tunnel Gully area, then popped over the hill to Maymorn, winched someone down (and possibly retrieved them) and after a bit, headed back to Trentham to refuel and were back out about half an hour later.
I was starting to wonder if they were using me (wearing bright orange running top) for ground target tracking practice. :-p
They'd also been flying around from Trentham on Thursday.
I used to work on a farm not far from a USAF base in the UK where A10's were based. Sometimes I'd be ploughing or whatever and all of a sudden a couple of them would appear, lined up with suspicious accuracy on the tractor! I imagine 6000 rounds a minute of depleted uranium rounds versus John Deere would have been a predictably one-sided outcome.....
One of my great regrets in life is that I will never get to fire one of those guns!