Preheat the oven to 170°C.
In a casserole pan, heat the oil over a moderate heat and add the scallops and prawns and saute with the garlic for six minutes until lightly browned. Set aside.
Add the onions, potatoes, celery, carrots, tomatoes, bay leaves and stock, season and bring to the boil then turn down to a simmer with the lid on for one hour. Carefully remove the vegetables and reserve and bring to the boil to reduce the fish stock by half. Add the wine and reduce by half again, add the cream, scallops, prawns and mushrooms, sugar snaps and simmer for 15 minutes, season.
Add the vegetables back in an mix through and serve piping hot sprinkled with chopped parsley.