1. Preheat the oven to 160 C, gas mark 2; season the lamb. Heat the oil in a large, ovenproof, lidded casserole dish and add half the lamb. Cook for 10 minutes, turning occasionally until golden. Remove the fillets and set aside on a plate, then repeat with the remaining lamb.
2. Set aside all the meat and add the onion and celery to the pan; cook for 3-4 minutes until slightly softened. Increase the heat, add the wine and cook for a further 2 minutes until almost completely evaporated.
3. Add all the remaining ingredients, mixing well. Simmer for a couple minutes, then return the lamb and any juices to the pan. Cover the pan and place in the oven. Cook for 2 hours 30 minutes, until the lamb is meltingly tender. Season and serve with mashed or boiled potatoes and wilted seasonal greens, if liked.