There is so much to that could be said and discovered about the monument ,sadly the sun horse theory and everything here has added nothing . The refutations have just left us where we started .
Fwiw , and only my worthless subjective view based on appearances from the plans , pics and GE (I'm discounting personal visits due to memory ) , the horse would not moving around the edge of the hill but continuing up what is left of the slope, prancing or galloping , it is unlikely to do such a sharp right turn when all the hard work has been done coming up the shoulder and the castle and barrow just straight ahead .