Place the raisins in a small saucepan and cover with water. Bring to a boil over high heat. Reduce the water until it becomes a syrup. Drain the raisins and rinse with running water.
Heat some oil in a saucepan over medium heat. Brown the lamb in a single layer in the oil. As pieces of meatbrown on one side, turn them over to brown the other side. Remove from the saucepan when browned and set aside. Add the onions, garlic, and celery to the saucepan and cook until the onions start to soften.
Add the browned lamb, raisins, tomato, red peppers, curry powder, salt, cayenne pepper [optional], and water to the saucepan. Bring to a boil, lower heat, cover, and simmer until the lamb is tender, about 2 hours.
Just before serving, mix in the lime juice. Divide the stew between heated serving plates and sprinkle with chervil.