Season the pork then place it in a large roasting tray. Arrange all the vegetables, herbs and spices around it. Pour in cider, cover with tin foil and braise in the oven at Gas mark 1, 150°C (300°F) for 3 hours. The belly is done when you can pierce the flesh easily.
To make the apple sauce: Simply peel, core and chop the apples and add them to a saucepan along with the sugar, butter and water. Allow to simmer gently for 10-15 minutes, stirring occasionally, until very soft. Taste before a serving and add a little more sugar if needed.
Remove the pork from the oven. Line another roasting tin or tray with greaseproof paper and carefully transfer the pork belly onto it. You can remove the bones at this stage. Set aside the original roasting tin to make the gravy.
Increase the oven to Gas Mark 6, 200°C (400°F). Place the roasting tin/tray into the hot oven and leave for 20-25 minutes to crispen the skin.
To make the gravy: Place the roasting tin over a medium heat. Drain off the fat. Then stir in the cornflour mixture. Continue stirring until it the sauce thickens. Taste and season then simmer for a couple of minutes. Pour through a sieve into a gravy boat.
To serve: Slice the pork and serve it with the apple sauce, gravy and roast vegetables.