In the end it all happened faster than expected. After saying goodbye to our first kitten on Saturday, I found a home for both of the other kittens (together!) immediately. In fact, I had multiple offers.
Because we were worried about Mum walking off to look for her kittens, she went first, on Tuesday evening. And then the kittens on Wednesday morning. I stayed in New South Wales overnight to babysit.
I want our cats back!