M&S Gastropub Fish Pie   Smoked haddock, king prawns, cod and Scottish salmon in a cheesy sauce topped with mashed potato and a parsley crumb Serves 1. Recreate that Gastropub experience at home with restaurant quality classics from M&S, for the ultimate night in. Our M&S seafood products have been sourced from fisheries and fish farms in a way that minimises their ethical and environment impact, while guaranteeing you the highest quality, delicious seafood you’d expect from M&S.