The Camelot Inheritance series
This photo (the one above) is from the beach at Downderry.
You can see the headland on the horizon, the little island is featured in the earlier books.
The island is a few hundred metres off Looe and is now a wildlife island. It used to be a handy spot for smugglers in the past - they could land barrels of brandy and other contraband brought over from France. Then they would wait until the coast was clear to bring them ashore. The penalty for smuggling could be hanging.