To make your braised red cabbage:
Place all of the ingredients into a large saucepan, bring to the boil and then reduce the heat to a simmer and cook for about 30 minutes until the cabbage has softened. Right at the end add in the cold butter and mix until melted. This will give a nice richness and gloss.
To make your pork:
Place your loin of pork in a large roasting tin. Pat the skin with kitchen roll and ensure it is completely dry. Rub 1 tablespoon of sea salt into the skin. Cover and leave at room temperature for 30 minutes.
Pre-heat the oven to 240C/220C fan/gas mark 9.
After 30 minutes pat the skin again with kitchen roll to dry. Rub in the remaining 1 tablespoon of salt.
Place the pork in the pre-heated oven and roast for 45 minutes.
After 45 minutes, add the sage leaves and lemon zest on the pork and turn the oven down to 180C/160C fan/gas mark 4 and roast for a further 1 hour.
Remove from the oven, check that any juices are running clear and allow to rest for at least 10 minutes. Serve with the red cabbage.