For the fish and chips, first preheat the oven to 250 °C. Mix the flour with the water and salt to a smooth dough and let it swell for 20 minutes.
Meanwhile, for the dip, mix the mayonnaise with yogurt. Add diced shallots and the pickled vegetables, mustard and horseradish and stir in. Season to taste with salt and pepper.
Peel the potatoes, wash them, cut them into sticks and dry them well. Heat the fat to 180 °C and deep-fry the potatoes in portions until they are almost cooked. Remove, reheat the fat and fry the chips again until they are golden brown. Remove, drain and keep warm in a preheated oven at 225 °C.
Wash and dry the fish, cut into portions, salt and pepper. Pull the fish through the batter in portions, deep-fry until golden brown and drain on kitchen roll.
Drizzle fish and chips with dip or vinegar in style and serve in a newspaper rolled into a bag.