Gnocchi: Bring the water up to the boil and sprinkle in the semolina, stirring steadily and cook, still stirring, until the mixture is thick. This takes about 1 minute. Draw the pan off the heat and add the chopped cooked bacon. Add the cheese and pour the gnocchi mixture into a shallow baking dish. Leave to cool. Cheese and bacon sauce: Melt the butter and stir in the flour. Cook, stirring for 1 minute. Draw the pan off the heat. Add the milk slowly, beating out the lumps as you go. Return the pan to the heat and stir until boiling. Simmer for 2 minutes. Fry the bacon rashers, chop and add to the sauce. Add all the cheese and mix well. Do not re-boil once you have added the cheese as the oil from the cheese will seep out. If you need to reheat do not add the cheese until you are ready to serve. To serve cut the gnocchi into rounds and put in a dish. Cover with the sauce and sprinkle some extra cheese on top. Put under the grill until the gnocchi has turned a golden brown.