Mix dry rub ingredients in a small bowl; set aside.
Prepare ribs by removing the membrane covering the bones. Pat ribs dry and cover them with the dry rub. Place on a tray then refrigerate, uncovered, overnight.
Place BBQ sauce ingredients in a small saucepan and stir well. Heat over medium-low heat until mixture boils. Reduce heat to low and simmer for 20-25 minutes until sauce is reduced to a ketchup consistency. Remove from heat and set aside.
To prepare on the grill--wrap ribs in heavy-duty foil. Heat the grill to medium-high heat on one side. Place ribs on UNLIT side and cook for 90 minutes.
To prepare in conventional oven--wrap ribs in foil as above and cook in a preheated 350F/180C oven for 90 minutes.
To finish with sauce--remove the ribs from the foil, brush generously with the sauce and cook over direct heat until sauce caramelizes; about 5 minutes each side. If you cooked them in the oven, place under the broiler until the sauce caramelizes.
For EU/UK--poultry seasoning is a blend of sage and thyme primarily. Equal portions of each is a good substitute or you could use all thyme or all sage to your taste.