Wash neck chops, pat dry. Wash the rosemary, pat dry and chop finely. Mix mustard, oil, buttermilk and rosemary. Spread the sauce on the cutlets, put them in a freezer bag, add the rest of the marinade, seal well and leave to marinate for about 3 hours. Remove, dab off some marinade and place in a grill tray. Place on a hot grill and fry for 10-15 minutes while turning. Season with salt and pepper