see the castle-an-dinas page - re the panoramic plate
Anyone fancy writing to them and finding out more?
When I was at the site I wrote down their contact details from the Info Board - Cornwall Heritage Trust, 6a Church St, Mevagissey, St.Austell, PL26 6SP. tel - (0209) 820277.
Ironically the Cornwall Heritage Trust are usually well respected for their sensitive preservation of sites, especially when compared to English Heritage.