Place the ham bone into a deep soup pot along with the soaked kidney beans.
Add the onion, bay leaf, scallions, thyme, garlic, and pimento berries.
Add the black pepper, salt, carrot, scotch bonnet pepper (keep whole and don't break), coconut milk, and 5 cups of the water.
Bring to a boil, then reduce to a gentle simmer. Cook with the lid slightly ajar for about 2 hours, stirring occasionally, until the beans are tender and beginning to break down. Add more water as needed and stir in the brown sugar.
Combine the flour, salt, brown sugar, and water to form a soft dough. Cover with a damp paper towel and allow it to rest for 10 minutes.
Add the dumplings to the pot along with additional water if needed (it will thicken futher, so I recommend adding at least another cup). Continue cooking for another 20–30 minutes. At this stage, you can remove the scotch bonnet pepper if desired. to control the heat, or break it to release that lovely Caribbean heat to the dish.
Taste and adjust salt, keeping in mind the stew will thicken further as it cools.
Turn off the heat, remove the bay leaf, thyme sprigs, and pimento berries, and serve warm. Serve with Coconut Rice.