[Brisbane] When to harvest passion fruit

We bought a passion fruit vine from Bunnings quite a while ago and we finally see fruits. The question now is, when do I harvest them?

We have about 20 fruits in the vine, different size, all green. Some of them are growing pruny but none of them are ripe yet (took one, and cut it open).

What should they look like when they’re ready to be picked? What time if year would that normally be?