T he best oysters of my life arrive on a polystyrene tray, eaten elbow-to-elbow with strangers at a table littered with empty shells and damp paper napkins. We huddle beneath a tarpaulin, sheltering from the fine spray of rain rattling on the roof, the wind whipping around the hulking CalMac ferry moored metres away, and the beady-eyed scavenging gulls. “Have you tried this? You have to,” says a woman who has driven from Glasgow just to eat here, pressing a rollmop herring into my hand. I take a bite, the thick skin giving way to sweet and salty flesh, juices running down my chin. Elegant dining this is not, but all the better for it. This is Oban Seafood Hut , tucked beside the ferry terminal for boats heading into the Sound of Mull. Diners shuffle around a shared table, listening for order numbers, with plates piled high with langoustines, crab and oysters. It’s cash only.…