The actor best known as Superintendent Ted Hastings in Line of Duty is bringing Homer and Heaney to County Donegal. Our writer joins him for oysters as he takes his dogs for a windswept walk along the shoreThere is a story about this seaside town, says Adrian Dunbar, as we lunch on oysters and crabcakes in Bundoran, on the southern edge of County Donegal. Outside Madden's Bridge Bar, the sky is the colour of porridge…