Score pork and rub with olive oil and salt.Heat covered bbq (outside burners only) to 250-300 degrees and place a shallow dish of water in the bbq (e.g. foil trays available from supermarkets)Place the pork in a roasting rack, place in covered bbq.Roast for approx. 30 mins and then turn burners to low.Pork will be cooked when juices run clear (approx. 30 mins per 500g)Rest for 10 minutes before carving.