Preheat the oven to 220C/425F/Gas 7.
Cut the pork into 2cm/¾inch-thick slices. Place the slices between two pieces of cling film and flatten out with a rolling pin to 5mm/¼inch thick. Discard the cling film and season the pork with freshly ground black pepper.
Heat a large ovenproof frying pan over a high heat. Add the olive oil, then add the pork and sear for one minute on each side. Squeeze the orange juice over the pork and top each piece of pork with some Stilton.
Transfer to the oven and cook for 3-4 minutes, or until the pork is completely cooked through and the cheese is bubbling.
Meanwhile, for the herb salad, place the herbs in a bowl. Drizzle over the olive oil and lemon juice and season, to taste, with salt and freshly ground black pepper. Mix together.
To serve, place the pork onto a warm serving plate and top with a pile of the herb salad.