Heat 2 tbsp olive oil in a heavy bottomed saucepan and add the celery,leek,carrot and garlic. Fry over gentle heat for 5 minutes. Remove.
Add remaining oil,and pinch the sausage meat into the pan. Break it up with a wooden spoon and fry until browned.
Return the vegies to the pan,and add the tomatoes,stock or water,thyme and bay leaves,and simmer,partly covered,for 30 minutes.
Cook the pasta in boiling salted water for 10 minutes,then drain.
Add the pasta,beans,zucchini,sea salt and pepper to the soup,and simmer for a further 10 to 15 minutes.
Serve with extra herbs,grated parmesan and a drizzle of extra virgin olive oil.