Ham & Leek Gratin

potato 30.0% , Beechwood Smoked Ham 17.0% , single cream 12.5% , water 12.5% , cow's milk 12.4% , leek 8.0% , medium mature cheddar 4.0% , extra mature cheddar 4.0% , wheat flour 0.0% , rapeseed oil 0.0% , corn flour 0.0% , pork stock 0.0% , salted butter 0.0% , salt 0.0% , yeast 0.0% , olive oil 0.0% , parsley 0.0% , white pepper 0.0% , sea salt 0.0% , caramel syrup 0.0% , paprika 0.0% , black pepper 0.0%