I have to say from what I can tell these are about the best deal I have found so far....
https://www.athom.tech/blank-1/au-plug
I bought one a few weeks back and Tasmota works perfectly.
My only complaint is they are a bit too wide to fit 2 side by side in a NZ plug socket.
I've just bought 5 more and with shipping works out to be NZ$27 per unit which is a pretty sweet deal!!!
Maybe there are some alternatives?