Cut the smoked haddock in pieces and put into a saucepan with the milk and sufficient water to cover. Add the parsley bay leaf, cover, and poach for 10 minutes. Transfer the fish to small plate and when cool enough to handle, flake the fish, discardins skin and bones. Strain 1/2 pint (300ml) of the cooking liquid into a measuring jug. Chop the hard-boiled eggs.
Melt the butter for the filling in a saucepan over low heat. Stir in the flour and cook gently for 1 minute. Gradually stir in the reserved cooking liquid. Bring to the boil, stirring well all the time to make a smooth sauce. Simmer for 2-3 minutes, add a squeeze of lemon juice and season with pepper. Add salt, only if necessary. Draw off the heat. Blend the egg yolk with the cream and stir into the sauce. Stir in the flaked fish and chopped egg and allow mixture to cool.
Spoon a little of the filling down the centre of each pancake and roll up carefully. Arrange pancakes in a greased ovenproof serving dish. Melt the butter in a saucepan over low heat, pour it over the pancakes and sprinkle with the grated cheese. Cover with kitchen foil and heat through in an oven heated to 375°F (190°C) or Gas no. 5 for 20-30 minutes until bubbling hot.