Refer to pack instructions and if necessary soak the ham the night before.
Pre-heat oven to 180°C/ Gas Mark 4.
Place the ham, skin-side up, in a deep roasting tin, add enough water to cover the base of the tin. Scatter the orange slices around the ham and cover tightly with foil. Cook the ham in the centre of the oven for 2 hrs.
While the ham is cooking, mix the WHITWORTHS DARK SOFT BROWN SUGAR, vinegar, orange juice and mustard.
When the ham has had 2 hours in the oven, take it out of the oven and turn up the heat to 220°C / Gas Mark 7.
Remove the foil, leave the ham until cool enough to handle, and then pour away any liquid in the tin. Using a sharp knife carefully cut away the skin to leave an even layer of fat. Use the tip of the knife to score the ham fat diagonally at 3cm intervals – first in one direction, then the other, to produce a diamond pattern. Liberally paint the glaze over the fat, then stud with the cloves at the points of the diamond shapes.
Roast the ham for 30 minutes until glazed and just beginning to char around the edges.
Serve warm or cold.