Yup, its true, you often find cracks in diesel heads, that allow the head to be used. Usuzlly as long as they dont head out into the water jacket itll be ok., since you have cracked heads already, it suggests to me that most of the 200's you see on the road will also have cracked heads, and are running just fine(well as fine as landrovers run anyway!!)
Unless of course you are just really unlucky! :lol: