Toss the lamb with the flour and salt. Heat the olive oil in a saucepan with a lid. Brown the lamb on all sides, then remove from the saucepan and set aside.
Place the onion in the pan with the spices and garlic and cook until soft. Add the wine and simmer until reduced by half. Add the beef stock and bay leaves.
Return the lamb to the pan, cover and simmer gently for 1 1/4 hours. Add the fennel and cook another 40 minutes.
Season to taste and stir through the chopped mint. Mix yoghurt and harissa paste together.
Serve the lamb topped with a dollop of the yoghurt mixture.