The 12 hours refers to Gavin's slow cooking method using sous vide - the lamb is vacuum-sealed and cooked at a precise low temperature for 12 hours straight. This incredibly gentle cooking process breaks down all the connective tissue and renders the fat, resulting in lamb that's unbelievably tender and falls apart without any effort. It's impossible to achieve this texture with traditional roasting methods. The long cooking time also means the lamb absorbs all those beautiful flavours from the red wine, rosemary, and garlic.
