Cook the bacon in a soup pot or dutch oven until crisp.  Remove from the pan with a slotted spoon to some paper kitchen towelling to drain.  Discard all but 2 TBS of the bacon fat.  Add the chopped onion, carrot and celery to the pan.  Cook, stirring frequently, over medium heat until they are beginning to soften.  Add the garlic and cook for a further minute. Stir in the chicken broth and drained beans.  Add the bay leaf and mixed herbs. Season to taste with salt and pepper.  Bring to the boil,then reduce to a slow simmer and simmer over low heat for about 45 minutes.  Remove the bayleaf and discard. Remove half of the soup to a blender and puree.  Return it to the soup pot along with the tomato passatta (sauce) and 3/4 of the bacon. Simmer for a further 15 minutes.  Taste and adjust seasoning as required.  Ladle into heated bowls and garnish the top of each serving with some of the remaining bacon and a bit of parsley if desired.