For the baked beans: Drain the beans, and put them in a large pan. Cover with water, and bring to the boil. Drain again, and return the beans to the pan. Cover with water, and cook for approximately 1 hour, or until just soft. Remove from the heat, and drain.
In a large saucepan, heat the rapeseed oil over medium heat. Add the bacon, and fry until crisp. Add the onions and garlic, and cook until the onions are soft. Add the tomatoes, tomato puree, sugar, vinegar and 2 1/4 cups water. Bring to the boil, and then add the beans. Reduce the heat to low, and cook for 1 1/2 to 2 hours, or until you have a thick sauce with soft, tender beans.
For the soda bread: While the beans are cooking, preheat the oven to 400 degrees F. Mix the flours, baking soda, salt, pepper, butter and buttermilk together in a large bowl, and form into a loaf shape of your choice.
Place the loaf on a baking sheet, dust with flour and bake in the oven for 45 to 50 minutes, or until the loaf is golden brown and sounds hollow when tapped. Remove from the oven, and leave to cool. Slice and toast when needed.
To serve: Season the beans with salt and pepper, and serve with slices of toasted soda bread.