Make the BBQ suace. Put all the ingredients in a small saucepan and stir together. Bring to the boil then reduce heat to a simmer. Cook for 10 minutes until sauce is slightly thickened.
Set aside to cool – this can be prepared in advance and kept in the fridge in a sealed jar.Preheat the oven to 180C (350F). Put all the ingredients for the spice rub in a small bowl and mix together.
Use a knife to get under the thin membrane that covers the bony side of the ribs and pull it off. It should come off quite easily.
Rub the spice all over the ribs, massaging it in so it sticks to the ribs. Place the ribs, meat-side down, on a wire rack set over a baking tray.
Cover with foil and cook in the oven for 1 hour. Take the ribs out of the oven and brush over with the barbecue sauce on both sides.
Return to the oven, covered, for 15 minutes. Take the foil off and cook for another 15 minutes. Rest for 10 minutes then use a knife to cut between the bones and separate the ribs. Serve with the rest of the barbecue sauce.