Cut the fish fillets into bite-sized strips or pieces, sprinkle with the juice of one lemon and refrigerate for about 1 hour before frying.
For the batter, sift the flour into a saucepan and add the salt. Stir with the wine, egg yolks and oil until smooth. Carefully fold the very stiffly beaten egg whites into the batter.
For the sauce, mix homemade or ready-bought mayo with the remaining ingredients and refrigerate until ready to serve.
Dry the marinated fish pieces on kitchen roll, season with salt and pepper, turn them in the batter to the other side and fry them on the spot in the fat heated to 180 degrees until crispy brown. Drain briefly on kitchen roll and arrange on a platter with lemon wedges.
Serve hot with tartar sauce and long grain rice or boiled potatoes.