Found a perfectly conical pit. The antlion was located just under the fine sand about 1cm down from the edge and 1.5cm from the bottom. The pit was functioning perfectly with a dead ant at the bottom and 3 ants, each of different species falling in during the 7 minutes of observation. The next day I went back again and the antlion had made a perfect pit 5cm away from the pit from the day before which was messy from searching for the antlion. Knowing it's the same individual and not wanting to disturb it again, I took a photo of the relocation distance and left it alone. Probably still there, feeding on ants from the multiple ant nest entrances nearby. The movement of the antlion was very interesting to watch - there are videos in the following link as well as a photo of the relocation (sorry about the videos which went out of focus - it was very difficult with my camera wanting to focus on the edge of the pit, not the bottom): https://photos.app.goo.gl/YrSkbpeyRwFLsFKm7
I returned to the same location on the 24th of December and it wasn't there anymore. The fine sand was concentrated on where the pit was on my second visit, but no sign of the insect.