Prepare the barbecue Gas/Charcoal for indirect cooking over medium heat (180° to 230°C).
With a sharp knife cut the rind around the sides of the pork, around the knuckle, and down the centre to free it on all sides, ensuring that you have cut right through the rind to the fat, but not into the flesh.
Place the ham on to the cooking grill. If the edges of the pork are hanging over the direct zone (above the fire), shield the sides with aluminium foil. Roast the pork over indirect medium heat for 2½ hours to blister the skin.
Combine all the ingredients in a saucepan and place over high heat on the stove top; bring to a boil. Reduce the heat to a simmer and continue cooking until the liquid is reduced. Take off the heat and leave to cool slightly.
Once the pork has cooked for 2½ hours remove the skin with tongs. Score the fat in a diamond pattern, being careful not to cut into the flesh, as the ham flesh will dry out.
After 30 minutes to 1 hour, using a basting brush, apply a generous amount of the glaze over the ham and continue cooking for 1 hour, glazing the ham every 20 minutes.
Once the ham is cooked and has reached an internal temperature of 68°C, remove the ham from the barbecue. The internal temperature will continue to rise 3° to 5°C while it’s resting. Leave to rest for 15 minutes before carving.
