Take the wrapping off the pork and leave it in the fridge for a day or two to dry out the skin.
Take it our of the fridge and let it come to room temperature for about an hour, which will help it cook evenly.
Pre-heat your oven to 230 deg C for at least 20 minutes so it’s nice and hot. Rub the skin with olive oil and salt. Plenty of oil and plenty of salt!!
Pop the pork into the oven and let it cook at that high temperature for 20-30 minutes, until the crackling starts to form, then turn the temperature down to 165 to 175 deg C and keep cooking.
Cook it until it gets to an internal temperature of 68 to 72 deg C and then let it rest.
If the skin hasn’t crackled you can put the pork under the griller, but be careful as it’ll crackle up very quickly!