Preheat oven to 350 degrees Fahrenheit.
Season lamb shanks with salt & freshly ground white pepper. In a large fry pan, over high heat, add 2 tablespoons olive oil. Add lamb shanks & sear on all sides. Remove from pan & set aside. Pour off fat from fry pans and put pans to the side.
In a heavy bottom pot with a tight fitting lid, over medium high heat, add 2 tablespoons olive oil. Add carrots & onions to brown. Deglaze with red wine & sherry vinegar. Add garlic, orange peel, bay leaves, parsley, thyme & peppercorns. Reduce liquid by ½. Add lamb stock. Deglaze the fry pans that the lamb shanks were seared in and place over a low flame. Deglaze with a little red wine and sherry vinegar and scrape the bottom of the pan. Add to the pot along with the browned lamb shanks & bring back to a simmer. Place on the lid or foil and cook in oven for 2 ½ hours or until meat easily falls away from the bone.
When the lamb shanks are cooked, remove from liquid & cover with foil to keep warm.
Strain the braising liquid into a saucepot & over high heat reduce by ½.