Prepare the Chimichurri sauce. Mix together the vinegar, parsley, juice from the lemon, garlic, chilli, oregano and 3 tbsp oil, season generously with salt and pepper. Allow it to sit for at least 10 minutes to release all the flavours into the oil.
Pre-heat BBQ for 2-3 minutes, season the steaks with a little salt and pepper and brush with oil.
Fry the steaks to your liking, once cooked cover with foil and leave to rest.
Spoon over each steak some Chimichurri and serve with fries and salad.