Melt the olive oil in a frying pan over a medium heat. Add the haddock, skin side down and heat for just a minute or two. Add the bay leaves, some pepper and pour in half of the milk (about 300ml), bring to a simmer then cover with a lid, remove from the heat and allow to poach until the fish flakes easily with a fork, about 15 minutes. Remove the fish from the milk and allow to cool. Reserve only half of the milk the fish was poached in.
Meanwhile, melt the butter in a saucepan over a medium heat and add onion and leek. Cook and stir for a minute or two, making sure they do not brown; reduce the heat if necessary. Add the potato, spring onions, parsley and some chives (reserve some chives for garnish) and cook and stir for a few minutes. Pour in the reserved milk from poaching. Allow to simmer gently for 10 minutes, until the potato is tender yet still firm.
Once the fish is cool, remove any bones and flake with a fork into fairly large chunks.
Pour the remaining milk into the saucepan and add half of the flaked haddock. Bring to a simmer but do not stir too vigorously, as you want to keep the fish chunks in tact as much as possible. Stir through the cream, taste and season. Ladle into warmed bowls, then divide the remaining haddock flakes between the bowls. Add some chopped chives and serve.