Pour the ginger beer, maple syrup, mustards and sugar into a medium sized pot and whisk together briefly, place on the stovetop over medium high heat and bring to the boil. Once boiled reduce the heat to medium and reduce by 2/3.
While the syrup reduces carefully remove the skin from the ham. Leave as much fat attached to the ham as possible and try not to cut into the fat.
Once the skin is removed score the fat in a diamond pattern keeping the diamonds approx 2cm wide. Poke 1 single clove into the middle of each diamond until the entire surface of the ham is clove studded.
Place the studded ham on a perforated baking tray over a solid baking tray. Once the syrup has reduced spoon it over the ham.
Place the ham into the oven combi setting 180 °C for 20 minutes. After 20 minutes pour the glaze from the solid baking tray into the pot and pour over the ham again. Return to the oven for a further 20 minutes and repeat this process a further 2 times.
Once the ham is golden remove from the oven and rest on the bench for 10 minutes. Pour the glaze over the ham a further 2 times while the ham rests and once the ham has rested place it on a large serving platter and in the middle of your table at Christmas Lunch.