To their credit, it was Ms Tana that dragged out the process, not necessarily the Greens. They booted her from the party, that ought to be enough to get her booted from parliament to begin with, but thats not the law. She then defended and delayed as much as possible to continue to milk the tax payer cow as much as she could forcing their hand.
Seems the Greens have some internal rules (mandate / constitution?) that has to be adhered to in these sort of circumstances, which they have done.
So long as she isn't entitled now to ex-mp perks, she will vanish in 1 to 2 news cycles.