Put the beans and pork belly into two separate bowls, cover with cold water and leave to soak overnight.
The next day, drain and rinse the beans and set aside. Drain the pork belly and pat dry on kitchen paper.
Heat a large, heavy based casserole over a high heat and add a spoonful of the duck fat from the jar. Fry the pork belly for 2 to 3 minutes until golden brown all over. Remove from the pan with a slotted spoon and fry the remaining meat, in batches, until golden brown.
Cut the sausages into chunky slices. Add a little more fat to the pan then add the onions and fry for 5 minutes until soft and starting to caramelise. Add the garlic and bay leaves and fry for a further 2 minutes.
Add the beans, cover with boiling water and simmer for 45 minutes until the beans start to soften. Add the browned meat and duck cover and cook for 1 hour until the beans are soft and the duck meat is falling off the bone.
Sprinkle with the chopped parsley and serve with the orange slices and some buttered kale.