Rub the quince with a towel, cut into quarters, remove the core and cut into slices. Heat the oil in a cooking pot. Reduce the heat, fry the quince in batches until golden-brown. Remove and set aside.
Heat the oil in the same cooking pot. Brown the lamb in batches for approx. 4 mins. per batch, remove from the pan, season. Reduce the heat, sauté the onions for approx. 5 mins. Add the plums and all the ingredients up to and including the cinnamon, sauté briefly. Pour in the water, bring to the boil, reduce the heat, cover and braise on a low heat for approx. 1 1/4 hours. Add the reserved quince and saffron, cover and braise for a further 45 mins. or so, season.