"My main argument has been, as Parker-Pearson re-iterated during his Durrington/Stonehenge investigations, why enter Stonehenge via the Avenue and then turn around to face the Midsummer Sunrise. "
That's what you do at Newgrange .i.e. enter in one direction then turn around .
It also assumes that there was a some observation going on ,at Newgrange too for that matter .