Sorry for the delayed responses, guys. I've been so busy at work with a proposal, I'm afraid I disappeared again for a while. Anyway, those aptly named Remarkable Rocks are on Kangaroo Island, near Adelaide in South Australia. They are just a large, natural rock formation. Visitors are free to wander about and climb on them as they like.
And yes, Hamish, that boat shot was with my iphone and instagram!