Some people prefer to roast lamb with the layer of fat that covers the outside still in place, while others wish to remove it. If you choose to remove it, use a sharp knife and cut off the sections of fat using a sawing knife.
To remove the hip bone from the leg, lay the leg, inner side up, wit the hip bone to your right, on your cutting board. Support the leg with your left hand and cut the meat from the bone. Move the leg around with your left hand, so you are always cutting in a comfortable position. Use the tip of your knife to cut the meat while keeping the cutting edge in contact with the bone. Work all around the bone until it is only at the joint with the femur. Then cut the ligament that holds the bone together. Discard the hip bone or save it for stock. Now, you have a loose flap of meat that was previously attached to the hip bone. You may want to remove this flap, so the leg is more uniform in appearance. Using the boning knife, cut all around the shank bone about 2 to 3 inches above. Scrape the bone to remove any remaining meat. This gives a neater appearance to the finished piece of lamb. You can hold the bone when the lamb is carved.