Mix together the 5 spice, star anise, cinnamon, soy, bay, chilli and honey. Add the duck legs and rub all over with the marinade. Put in the fridge for at least 2 hours or overnight.
Preheat the oven to 180 C Gas Mark 4. PLace the duck legs in a large casserole with the juice of the mandarin. Cover tightly and cook for an hour.
Remove from the oven and stir in the vinegar, ginger, mandarin peel and the plums.
Return to the oven uncovered and reduce heat to 160 C Gas 2. Cook for a further 1-1 1/2 hours . The duck should be tender and falling off the bone, and you should have a rich and sticky sauce. Add a splash of water during cooking if the sauce is drying out to much.
Keep covered until ready to serve with rice and greens.