Hi there. I overcame this particular problem myself after a season at a hotel up in Scotland. I first braise the pork belly skin side up, so as not to submerge the skin. After a good few hours of braising, I press the belly overnight in the fridge. Next day when its cooled, score and salt the skin and then cut it into your desired portion shapes/sizes ready for service. Now when you get an order on, get the pork in a pan with some veg oil skin side down and get it nice and golden. Its better to start with a cold pan, as with duck. When that skin is nice and caramelised whack it in the oven, still with the skin side down. When its heated through nicely its ready to serve, and when you flip it over you should see a beautiful, hard as nails crispy skin.