In a saucepan, combine the cream with a whole half onion and a bay leaf. Leave to infuse on a low heat, then insert your seafood. Poach lightly until soft and flakey. Remove the prawns before the cod as the cod takes longer to cook. Reduce the cooking liquid until slightly thicker - then strain.
Chop the swede removing the top and bottom first to allow the swede to be more stable when removing the skin. Then chop the swede into smaller wedges before boiling in a seasoned pan of water and lemon juice. Boil for 10-15 minutes until soft. Strain, then put back into the pan.
Mash the swede with butter and milk, until smooth in consistency with no lumps. Season to taste and set aside ready to assemble your fish pie.
In a heatproof dish, insert the seafood followed by the reduced liquid. Pop the swede mash on top using a spoon or you could pipe the mixture. Bake for 10 minutes until warmed through.
Remove from the heat and serve with a side salad and a wedge of lemon.