Food in A Question of Death - Whole Baked Fish

In The Miracle of St Mungo Phryne reinacts the miracle to help Lucy save face in retrieving her locket by hiding it in a fish. Here is the recipe for whole baked fish (minus any jewellery):

Ingredients:
1 whole fish (about a kilogram) sea bass, salmon,
trout or snapper
1 tbsp chopped parsley
8 tbsp bread crumbs
1 small onion, finely chopped
1 tsp lemon rind
1 tsp salt
1 tbsp butter

Method:
Clean and scale the fish, remove the insides and eyes, and cut off the fins. Mix all the remaining
ingredients together, except butter, to make the stuffing. Stuff the fish with half the stuffing, and
sprinkle the rest in a baking dish. Lay the fish down in the baking dish and dot fish with butter, then
cover with a lid or foil and bake for ten minutes. Take off the lid and bake for a further ten minutes,
until you can pull a bone out cleanly.