Put 4 tbsp of barbecue sauce along with the rest of the ingredients into your slow cooker. Top up with enough water to cover (roughly 1.5l). Slow cook on Low for 8 - 9 hours until very tender but not completely falling off the bone.
Heat the oven to 220C/ 200C fan/ gas mark 7. Remove the ribs from the slow cooker using a slotted spoon or tongs. Handle them carefully as the meat will be very tender and may start to fall off. Baste with the remaining barbecue sauce and lay on a foil-lined oven tray. Cook for 20 - 30 mins until starting to crisp on outside. Alternatively, cook on the barbecue, turning from time to time until piping hot throughout.