Fungus or caterpillar?

I was fairly sure I would find what I was looking for. There is a group of Black Wattle Acacia mearnsii growing on our bush block at Homerton and in previous years I had found the Vegetable Caterpillar Cordyceps gunnii growing under them, so that was where I headed. Cordyceps are wonderful fungi and I love showing them to the uninitiated, especially children. There is a lovely sense of horror and disgust mingled with astonishment when they see a fungus growing out of the head of a large dead caterpillar, a moth larvae. We were expecting a family of children to visit hence my reconnaissance. I was pleased to find them growing in abundance under the wattles. The pleasure was doubled when I found the colony of Trim Orchids nearby. This area is entirely natural regrowth as a result of putting up a fence about twenty years ago to keep stock out, so its very rewarding to see nature getting back to business.

Next day, armed with a spade, I took the boys down to do some 'excavation', and was astonished to see that a lot of the fungi had been pulled from the ground. They hadn't been eaten but there were very few with the caterpillar part still present so I'm puzzled.

Was the caterpillar broken off as the fungi was being pulled up? I tried pulling several very gently out of the wet ground and the caterpillar broke off every time, so I don't know how an animal could have been more successful.
Was the fungi pulled up just to eat the caterpillar?
What animal did it and how? Echidnas? Possums? Kangaroos? A bird?

Now a true naturalist or scientist would have gone back at night with a spotlight. Not me. I was already exhausted from sitting up too late to watch some mad bike riders race around Europe.