Combine orange juice, brandy, sugar, ginger and mustard in a small saucepan. Stir on low heat until sugar dissolves. Simmer for 5 mins, or until syrupy.
Meanwhile, cut rind from around shank of ham, 10cm from knuckle. Using your fingers and starting at base of the ham, carefully remove skin. Score fat in a 1cm diamond pattern, taking care not to cut all the way through to the ham meat.
Line a large baking pan with foil. Place ham in pan and brush over half the glaze. Bake for 1 hr, brushing with glaze every 20 mins, until golden. Slice ham and serve drizzled with remaining glaze.