Hey Simone, thanks so much for your ID on the wasp. My husband, whose insect photos I post, likes to have fun working out species ID. He couldn't work out whether it was Stenarella victoriae or Xanthocryptus novozealandicus. He thought that the ovipositor on the wasp he photographed might be too short for Stenarella? Is it one of those cases where there is quite a bit of variation in ovipositor length within the species?
I now realise ovipositor length is a very clear differentiator, S. victoria has a very long ovipositor, while the X. novozealandicus is short. So my original id was wrong.