As an ex-Camborne man I ought to recognise many of the Wycliffe locations but it's been many years since I was last down in the Duchy! In the episode "To Sup with the Devil" which I saw on ITV3 recently, where was the beach area that Darren Tighe and Helen Masters (ie, the young lad and DC Lane) visit about halfway through with all the ruined mining engine houses? Is it Porthtowan? And the rocks near the end where he handcuffs her, is that Prussia Cove?