Dobfarm, your suggestions are very interesting, and I thank you enormously, but to be honest, I still haven't seen a clifftop with that weird formation on the top. Lots of caves, yes, but no 'hanging rock' that fits.
Still, I've had enough of looking I think, and thank you all for your efforts.
I will see what ebayers make of it, as it IS for sale after all.
thanks
tim