Heat the oil in a large saucepan over a medium heat, then add the onion and bacon. Cook for 8-10 mins until the onion is soft and the bacon is cooked. Stir in the flour, then cook for a further 2 mins.

Pour in the fish stock and bring it up to a gentle simmer. Add the potatoes, cover, then simmer for 10-12 mins until the potatoes are cooked through.

Add the mace, cayenne pepper and some seasoning, then stir in the milk.

Tip the fish pie mix into the pan, gently simmer for 4 mins. Add the cream and shellfish, then simmer for 1 min more. Check the seasoning. Sprinkle with the parsley and serve with some crusty bread.