Remove the string from the shoulder of pork, if it has one, and butterfly the shoulder. Score the skin with a small paring knife ensuring you don’t cut into the flesh.
Mix together all the remaining ingredients and season well. Create a sausage shape with your stuffing and place in the middle of the shoulder with the skin side facing downwards, roll the joint and tie using butcher’s string.
Boil half a kettle of water and carefully, over a sink, pour the water over the joint to soften the skin. Apply olive oil and rub a generous amount of coarse sea salt into the skin.
Preheat your grill to a medium-high indirect heat, and cook the pork with a drip pan underneath for approximately 2-2 ½ hours or until the pork has reached 75°C in the centre.