Place the ham in a large heavy based saucepan, add the studded onion, carrots, bay leaf. Add enough water to cover the ham completely. Bring to the boil then reduce the heat and allow to simmer for about 1hour approximately. ( or 20-25 min / 500g depending on the size of your ham.) Remove from the heat and allow the ham to cool in the cooking liquor.
In a small sauce, simmer the marmalade, treacle, mustard, chilli and whiskey for a minute, stirring until the mixture combines together.
Preheat the oven to 160˚C/ 325˚C.
Place the boiled ham on a roasting tray. Using a sharp knife carefully remove the skin from the ham, then gently score the fat. Stud the ham with cloves.
Spread the glaze over the ham with a spoon.
Place into the oven for 20 minutes minimum for a small ham or 45 minutes for larger ham on the bone until golden brown then remove from the oven.
Using a pastry brush, brush any missing spot of the ham and let it rest for 20 minutes.
Carve the ham and enjoy warm.