Take a large pan big enough to hold your gammon, leaving it in the vacuum bag immerse in water to boil on the hob. The vacuum bags will withstand the cooking this holds in the moisture and flavour of the ham. Cook the ham for approx an hour per kg size of joint. Or alternatively if you have a meat probe test the centre temperature to 75 degrees c to decide when the gammon is cooked.
When the gammon is cooked let it cool by running cold water over the joint in the pan. When the meat is cool enough to handle remove from the bag, cut the strings and carefully remove the skin leaving the fat on the joint sliding your fingers to between the two. Score the fat with a crisscross pattern and brush on using a pastry brush a mixture of equal parts honey and mustard.
Decorate with cloves by pushing them into the fat if you wish and bake in a preheated oven at 200 degrees c for 20 minutes just enough to colour the glaze to a golden brown but not dry the ham.