Chop the fish bones into smaller pieces and set aside. Heat the olive oil in a large stockpot and sweat the onion, leek, celery, fennel and garlic for 4-5 minutes. Pour in the white wine and let bubble until reduced to a syrupy glaze. Add the herbs, peppercorns, lemon slices and fish bones to the pot.
Cover with 2 litres cold water and bring to a simmer, skimmi