I had a great conversation with another gardener on a Facebook group about aphids. She was saying that you should leave the aphids on the plants so there's enough there for the predators to feed on when they do turn up and they'll stay and multiply. My first reaction was, 'tried that, doesn't work!' That's probably because once the ants turn up to farm the aphids, they also keep the predators away and we have lots of ants!
However, quail like to eat ants so on checking the aphid infested tamarillo again in our quail run I found these critters and ate humble pie! I nearly missed them, they are so small. On the left seems to be some sort of tiny ladybird and on the right is a ladybird larva, I'm thinking from a standard ladybird. The other gardener also told me she finds even smaller ones than this on her plants.