Marinate the ox cheeks in the wine and herbs overnight. Remove the ox cheeks from the marinade and pat dry. Strain the marinade, discard the herbs and reserve the liquid. Heat a heavy-based casserole pot large enough to comfortably fit the cheeks. Add some olive oil to the pot and brown the ox cheeks well on both sides, seasoning with salt and pepper. Remove to a plate. Add a little more olive oil to the pot and add the chopped onion, carrot, celery, garlic and pancetta. Turn the heat down a little and gently cook the vegetables until they are golden brown and a little soft. Add the ox cheeks, the rosemary, salt and pepper, the wine and the stock. Cover with a lid and simmer very gently for about two hours or until soft when pierced with a knife. You will need to skim any scum that rises to the top and check from time to time there is sufficient liquid in the pot to cover the cheeks.
Once the cheeks are done, remove to a plate and turn the heat up high. If there is still plenty of sauce in the pot you may want to reduce it a little. I like to thicken the sauce lightly with a little butter and flour in a bowl, combine the butter and flour so it forms a paste and whisk into the simmering sauce. Cook for five minutes, check for seasoning, add the cheeks and serve.