I know the Cairns of Castella, these are way off to one side of where I'll be putting up antennas which will be in a field that has been used for generations and has half a dozen 1 ton milk cows wandering and crapping all over it much of the year.
There is a pre-history field system https://historicengland.org.uk/listing/the-list/list-entry/1015697 but I'll not be on that bit either but I suspect walkers that go around the island will probably just wander through the downs without realising what they are until they see the Cairns.
What they might spot are:
Periglis beach where I MIGHT if time have a go at 160m during the night.
Cove Vean bay where there is a very shallow section, where I might test a 4 square
Something known as the Giant's Punchbowl
I suspect I might post contest just wander around to Gugh and see the sand bar
before going to the Turks Head.
That is bishops light house in the background... I did a drift dive down about 20m passing that at about 12 knots the current is so strong (that was back in 1986!)