I didn't know you were in NZ! Top dream place I'd love to go. My friend who moved there said of NZ "it's all the best parts of Aus, without all the deadly things" Apparently there are still a few terrifying things there! I'm so sorry for what your grandfather has gone through. That's awful.They’re one of the most common ones there. Invasive in New Zealand as well, came on a cargo ship. Found one under the wood pile