Rinse beans. In a large saucepan combine beans and 4 cups water. Bring to the boil; reduce heat, simmer for 2 minutes. Remove from heat. Cover and let stand for 1 hour. (or, skip boiling the water and soak beans overnight.) drain and rinse beans. In the same pan combine beans and 4 cups fresh water. Bring to the boil; reduce heat. cover and simmer for about 75 minutes or until beans are tender, stirring occasionally. drain beans, reserving liquid. In a 2-pint casserole, combine beans, ham and onion. stir together half a cup of the bean liquid, passata, chilli peppers, brown sugar, chilli powder, salt and mustard. Stir into bean mixture, bake, covered, in a 160C/325F/Gas Mark 3 oven for about an hour. Uncover and bake for about 45 minutes or more to desired consistency.