Before cooking, I soak my ham for 24 hours in several changes of water, others don't. Soaking works for me, giving a less salty product.
Simmer the ham with a couple of onions, bay leaves, a few cloves and a few black pepper corns for 20 minutes per 450g. The ham should be poached rather than boiled, so a very gentle simmer is all that is needed.
Remove the ham from the stock and allow to cool for 10 - 15 minutes.
Cut away the skin but leave as much fat as you can. The strings can be removed at this stage as the ham should now have "set".
Score the fat into a diamond pattern and smear English mustard over the surface. Sprinkle with brown sugar and a drizzle of honey.
Bake in a preheated oven (190°C) for about 30 minutes or until the glaze slightly caramelises. Watch that it doesn't burn. The ham is already cooked you are just caramelising the glaze at this stage.
Remove from the oven and leave to rest for 15 - 20 minutes before slicing or leave to slice cold.