Serves 8  Ingredients: Topping:  1 kg potatoes, peeled and cubed  125g butter 125ml warm milk  Filling:  600ml full cream milk 5 bay leaves  500g smoked haddock 500g prawns, deveined & shell removed  500g white button mushrooms, sliced  50g butter  1 large onion, diced 1 large carrot, peeled and sliced  1 large leek, washed and sliced…