Arrange four fillets, skin side down, in the base of a deep-sided baking tray or large frypan. Scatter lemon rind and onion over fish.
Place remaining fillets, skin side up, over bottom layer to resemble four whole whiting. Add lemon juice, water and bayleaf. Season with salt and pepper. Cover tightly with foil.
Place over a gentle heat. Simmer for 5 minutes or until fish is just tender. Using a slotted spoon, carefully arrange fish on a serving platter. Cover with plastic wrap and chill.