A lot of the effort is in the preparation. I got some great quality pork belly and a thin loin piece from a really good, local, farm shop. I took off the ribs, trimmed it, and rolled it myself. The rolling and tying took a couple of goes before I was happy with it, but it was worth it. Then it was mostly just time and judiciously applied heat!

Edit to add: a couple more thoughts! I butterflied the belly so it opened like a book. Then, using mustard as a binder I seasoned the meat and the underside of the skin with salt, pepper and garlic and just a hint of smoked paprika. Then I salted the skin and roughly rolled it and let it airdry in the fridge for about 36 hours. I also made some stuffing with crushed pinenuts, parsley, onion, apple, and chorizo which I cooled and then I layered on the stuffing and did the proper roll and tie about an hour before it went on the spit.