Preheat oven to 160oC fan forced.
Combine orange rind, orange juice, sugar, half the honey, mustard and garlic in a small saucepan over medium-high heat. Bring to the boil. Reduce heat to low. Simmer for 8 minutes or until slightly reduced.
Meanwhile, using a small and sharp knife, cut around the shank about 10cm from the end. Carefully run the knife under the rind, around the edge of the ham. Gently lift off the rind in 1 piece by running your fingers between the rind and the fat. Discard the rind.
Use a small sharp knife to score the fat in a diamond pattern. Add a small amount of water to a roasting pan. Place the ham on a wire rack in the pan.
Brush the ham with the pre-made syrup, reserving 1/4 cup. Bake the ham for 40 to 50 minutes or until golden brown (basting occasionally).
Meanwhile, place nuts, all-spice, salt flakes and pepper in a food processor. Process until finely chopped. Add reserved syrup and pulse until combined. Drizzle ham with half of the remaining honey. Press nut mixture over ham. Drizzle with remaining honey. Bake for a further 20-30 minutes or until nuts are golden. Set aside for 15 minutes to rest before carving.