Just to answer your last question as well.
The generic battery for the FP1 won’t fit at all.
But unfortunately I have no other idea besides the ones already posted. 
Edit
Maybe you can try jubatec.
They sell a FP2 battery and it seems, they do ship worldwide (at least it is possible to select NZ as destination). Their homepage is German or Dutch only - unfortunately.
Edit 2:
@Alex.A was faster, but here’s the source. 