Prepare the stuffing by toasting the bread, then removing the crusts. Scrunch the toast into a bowl, then bash the pine nuts in a pestle and mortar and add to the bowl. Pick, finely chop and add the sage, then coarsely grate and add the pear along with a good pinch of sea salt and black pepper. Drizzle with 2 tablespoons of oil and squeeze it all together with your hands. Set aside until needed.
Bash the fennel seeds with the sage and a pinch of salt and pepper until you have a fine rub. Muddle in 1 tablespoon of oil and work the mixture all over the pork, making sure you get it into all the incisions. Peel and quarter the onion. Put the bones and onion in a roasting tray that will snugly fit the pork loin.
Lay the pork on a board, skin-side down. Use a knife to make an incision between the loin and belly meat, along the length of the pork joint, to create a flap. Pack this space with stuffing and season well. Roll the belly around the loin and tie the joint tightly with 5 or 6 pieces of string to keep it all in place. Place the prepared pork on top of the bones.
Place in the oven and cook for 30 minutes (this will help give you super-crisp cracking), then reduce the temperature to 190ºC/375º/gas 5 and cook for a further hour, or until the meat is cooked through and the crackling is crispy.
Prepare the fruit and veg by cutting the pears and fennel into 6 pieces, peeling and quartering the onions, and peeling the garlic bulb, then smashing up the cloves.
Add the pears, onion and garlic to a separate roasting tray along with the rosemary, fennel, bay and any remaining sage. Drizzle it all with oil and pop in the oven on a shelf underneath the pork and roast for 45 minutes to an hour, or until the vegetables are soft and caramelised.
Once the pork is cooked, move it to a platter, cover with tin foil and a clean tea towel and leave to rest while you make the gravy.
Using tongs, remove the bones from the roasting tray. Place the tray on the hob over a medium heat and add the perry. Simmer until reduced slightly, then add the flour and stir it into the juices for 2 to 3 minutes.
Pour in the stock, then continue to simmer until thickened, stirring regularly. Once you're happy with the consistency, carefully pass it through a sieve into a jug.
Serve the roasted pear and vegetables with the pork and gravy, ensuring everyone has their fair share of the crackling. Delicious served with steamed greens.