Rub the lamb all over with olive oil and season all over with salt and pepper. Heat a very large Dutch oven such as Le Creuset over medium-high heat until its hot. Add the lamb and sear on all sides for about 12 minutes, until its browned all over. Remove the lamb to a plate.
Add the wine and 2 cups of water to the pan and cook for a minute or two, scraping up all the brown bits in the bottom. Add the garlic, rosemary, thyme, and bay leaves and the lamb on top. Place the lid on the pot and bake in the oven for 4 hours, basting occasionally. (If you dont have a lid, you can cover it tightly with 2 layers of aluminum foil.)
After 4 hours, the lamb should be incredibly tender and falling off the bone. Remove the lamb to a plate, cover it tightly with foil and allow it to rest. Strain the sauce into a saucepan and bring to a boil. Lower the heat and simmer for 10 minutes to reduce. The lamb will be too tender to slice; serve it warm with spoons and the sauce.
Before you buy the lamb, measure the diameter of your pot. If the lamb is longer than your pot, ask the butcher to cut off the shank end of the lamb and cook both pieces together in the same pot.