I have been intrigued by the Swindon Diamond Stone for a long time now, and I have suspected that each of the two horizontal corners on the southern rockface hosts a pointy nosed deity, one pointing east and the one in this photograph, pointing west.   Seems to me that the existence of the left or westward looking facial profile above is proven by the carving of the small eye slit, highly reminiscent of that carved on to the nearby Stone 50 which you can see here.   By the way I suspect the existence of one or more broadly comparable corner faces on the remaining stone of the Longstones Cove.