Heat oven to 160ºC . Have ready a foil-lined shallow roasting pan fitted with a rack. Place ham on rack and bake about 1 hour. Pour juices into a 1 litre saucepan and place in freezer about 10 minutes to cool (so fat congeals). Pour syrup over ham and return to oven. Bake half hour longer, basting once with syrup from pan. Meanwhile remove saucepan from freezer. Skim off and discard fat. Whisk in flour and mustard until smooth. Whisk in water and Worcestershire sauce. Increase oven temperature to 375 degree and baste ham with drippings in pan. Bake about 15 minutes longer until meat thermometer inserted in thickest part of meat, not touching the bone, registers 60ºC . Remove ham to cutting board. Let stand 15 minutes before carving. Add drippings from roasting pan to saucepan. Bring to a boil over medium heat, whisking often. Boil gently 2 to 3 minutes until thickened. Pour into gravy boat. Makes 8 servings ham with leftovers. Per 4 ounce serving ham and 3 tablespoon gravy: 310 cal, 26 g pro, 26 g car, 10 g fat, 67 mg chol, 1,719 mg sod.