The formation on the right changes a bit from below but the one on the left still looks like a bird.
On the way back to the car a Dinosaur Park ranger stopped and chatted with me and asked if I'd been to the arch. I asked him if it had a name and he said no.
Because it takes a lot more effort to see this from the bottom and it looks more like two birds kissing from the top and the fact it does not have a name it does now.
The name I've given it is "The Kissing Birds Arch",