1/4 cup molasses (if you don't have it, add a little more brown sugar and worcestershire sauce, I wouldn't really substitute with any other syrup, but you do you.)
1 teaspoon worcestershire sauce (check out Spring Gully brand if you're in Australia for a fish-free option)
1 teaspoon liquid smoke (if you don't have any, go a tablespoon smoked paprika or chuck in a chipotle chili in adobo sauce)
1 cup water
Soak the beans in the 2 cups water overnight.
The next day (get a move on early, these take forever!) simmer the beans 2-3 hours with the teaspoon of salt over low heat. They should be reasonably tender. You may need to keep topping up the water. When done, drain.
In a baking dish, add beans, tomatoes/passata, molasses, mustard, sugar, worcestershire sauce, liquid smoke and water. The mix should be quite liquidy, but add a bit more water to fully cover the beans if it isn't already.
Bake at 100C for about 8 hours or 180 for 3-4 hours, topping up the water as needed. I cover the beans with foil for the first few hours and leave the foil off for the last hour. I also check the flavour in that last hour - sometimes you need a little mustard, sometimes an extra splash of worcestershire or liquid smoke.
Bake until the beans are soft and the sauce has reduced to a thick, smoky-sweet sticky coating. Add a little water to loosen as you stir, and get stuck in!