Prepare the crepes. In a blender, combine eggs, milk, water, flour, melted butter, salt and pepper. Blitz for about ten seconds. It should be the consistency of thin pancake batter.
Cover the mixture in plastic wrap and place in refrigerator for an hour.
Heat a 22 centimeter non-stick skillet over medium heat. Brush the whole surface of the pan with melted butter. Ladle three tablespoons (45 milliliters) of batter to the centre of the skillet and swirl the batter to coat the bottom of the pan evenly. Cook for 30 seconds and loosen the crêpes from the pan and flip in one fluid motion. Cook for another 15-20 seconds and remove to a plate covered in parchment paper.
Repeat until you have used all the batter and made six to eight crêpes. Cover with a towel until ready to serve.
Prepare the sauce.
Set up a double boiler with two cups (500 milliliters) of water.
Add egg yolks and lemon juice to a stainless steel bowl and sit the bowl on top of a pot of boiling water. The bowl should be large enough to fit over your pot without touching the water. Vigorously whisk yolks with a balloon whisk. If eggs become too hot, lift bowl off the pot for a few seconds. Whisk until egg mixture thickens up and almost doubles in volume.
Remove bowl from heat and add salt and pepper. Gradually whip in the melted butter – and keep whisking until the mixture is thick and doubled in volume again.
Keep the sauce warm until ready to use. If it needs thinning out before serving add a touch of warm water.
Prepare the seafood.
Place shallot, celery, chives, and crabmeat in a bowl.
Season scallops and sear in a pan with melted butter. Break up the lobster meat and add to scallops pan to warm through for one minute. Add lobster and scallops to the bowl of crabmeat. Pour in more melted butter and mix all together.
Add gruyere to the mixed seafood bowl. Spoon seafood mixture into middle of each crepe. Fold crêpes into logs, and place in a pan lined with parchment paper. Drizzle with hollandaise and top with more grated gruyere cheese. Place under the broiler for three minutes or until cheese is melted and golden.