Preheat oven to 120C.
Heat some oil in a large, heavy base frying pan and sear the lamb heavily in a pan.
Transfer to a small pot or ovenproof pan, cover with the lamb stock alongside the clove of garlic and bunch of thyme. Cover with a lid or some foil and place in the oven for 2-3 hours.
Once the lamb is tender and soft, skim any fat from the surface of the pan. Strain the stock and transfer to a saucepan and place on the hob to reduce the stock. Reduce the stock to a thick glaze, then return to the lamb to coat the meat.
Bring the chicken stock to the boil and add the polenta, stir whilst cooking on the stove for 10 minutes unit the mixture thickens and softens. If necessary adjust the consistency with hot water to form a loose paste.
Add the grated cheese and butter and stir to combine. Season with salt and pepper.
Preheat the grill or a griddle pan. Drizzle the peppers with a little olive oil and place under the grill until the skin blackens and chars. Cut the peppers in half, scoop out of the seeds and slice the peppers into thick wedges.
Prepare the gremolata. Finely chop the parsley, olives and chilli and transfer to a small bowl, zest the lemon and add to the mixture alongside a drizzle of oil and pinch of sea salt. Dress the peppers with the gremolata.
Serve the warm sticky and glazed lamb with some of the cheesy polenta and herby peppers.