Preheat the oven to 180°C, gas mark 4. Mix the salt and vinegar together in a small bowl. Spread out on a large baking tray and cook for
20 minutes, until the salt is completely dry.
Line 2 large baking trays with baking paper. Toss the potato wedges with the olive oil and season. Spread out in a single layer on one of the prepared trays and cook for 25 minutes, or until crisp on the outside and soft in the centre.
Meanwhile, combine the eggs, lemon zest and juice in a shallow dish and tip the cornflakes into another.
Dip the cod into the egg mixture, shake off any excess, then coat with the cornflakes. Arrange on the other tray and cook for 20 minutes, turning halfway, until golden and crisp.
Divide the fish and chips among plates or baking paper parcels. Serve with lemon wedges and sprinkle with the malt vinegar salt.