I think you are potentially backing the wrong horse by going up against this HoD. If they are getting good grades and the Head put them in place to do the job then if you rail against this you are possibly going to be seen by the head as trying to undermine their decision making. There is only going to be one winner in that scenario and it is not going to be you. As pointed out you can put your own SoW in place if you feel it's an issue. We don't have any SOW's strictly in place here either but the whole course is mapped out on the VLE which sounds quite similar to the way you describe what you have at your place. To be honest it's also very difficult for anyone on here to comment without having first hand experience of your school.