Make a dry rub mixture by mixing together the garlic, rosemary, sage, some salt, pepper and fennel pollen. Mix together the vinegar and honey. Coat the lamb with olive oil and the dry rub mixture and place on a small baking sheet with a rack.
Roast for 4 hours, basting with the vinegar mixture every 45 minutes. Cover with tin foil to let rest.
For the beans:
Meanwhile, place the beans in a pot and cover with cold water. Add the onions and rosemary and bring to boil. Reduce to a simmer and cook until the beans are cooked through to the center, about 2 hours. Remove from the heat and drain.
Dress with some olive oil, the sage and some salt and pepper.
For the lamb loin:
Preheat the grill to high heat.
Coat the loin pieces with olive oil and sprinkle with salt and pepper. Sear the meat on the grill evenly on each side, 2 minutes per side. Let rest before serving with the lamb roast and beans.