A loin of pork from a traditional breed will have far more fat than you are accustomed to seeing on regular farmed pork. The fat will be sweet and delicious, but still may be a little too much for some people. Cutting it away means losing the crackling, so the choice is yours.
Use a boning knife to cut the loin free of the rib bones. This is easily accomplished (providing the butcher has removed the chine or backbone) by following the line of bones downwards with a sharp knife. Keep the blade right next to and always pointing towards the bone and you will not lose valuable meat, or valuable fingers, should the knife slip. The bones you cut away will be excellent for spare rib dishes another time.