First make the batter. Put the flours in large bowl, make a well in the centre, add the eggs, milk and water and beat together until smooth. Allow to stand for 2 hours before cooking.
Heat a non-stick frying or crepe pan and wipe very lightly with vegetable oil. Ladle in just enough mixture to cover the bottom of the pan tip the pan to make the mixture travel and coat the base evenly but lightly. Allow to set over a medium heat, then flip with a palette knife. Cook for a further minute and then turn out. Repeat until all the batter is used. You should end up with about 18 pancakes, even if you have had to throw the first one away. You can stack them up with baking parchment between the layers.
To make the filling, heat the oil in a pan over a medium heat, add the garlic, bacon and leeks, and cook for 10 minutes, stirring constantly. The aim is to cook the leeks until they are soft and any excess liquid has evaporated. Add the seasoning. Remove from the heat and stir in the grated cheese and creme fraiche.
Place a spoonful of mixture on each pancake and fold into quarters to make little triangular cones. Serve at once.