When the ham has had its time, remove the roasting tin from the oven and turn up the heat to 220°C / fan 200°C / Gas 7. Remove the foil, leave the ham until cool enough to handle, 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.