Cooking lamb that falls off the bone
Brown the lamb on the stove top, or high temp oven. Then, braise rather than roasting. That means 2/3-3/4 of the pan is filled with liquid after you put the lamb in first. For flavorful liquids, consider beef, chicken or veg stock. In Malaysia I see a lot of grape juice substitutions for wine in traditional Italian recipes that call for braising. But I would dilute it, so it's not overly sweet. Perhaps some tomato juice would work as well.