Will grab a ftf on this one many years after it was published. Was a bit tricky pulling up here in the campervan but we managed to get far enough off the road to be safe.
Have included 2 photos. One showing mr beetle standing next to the white marker post near the trig and a close up of the inner circle of rocks.
Could not unearth the actual disc but the tell tale circle of rocks was there surrounded by a large circle of rocks. Don't know if the white marker post has any significance but it was interesting and appears to have a convict arrow mark in the bottom.
Thanks.