Clear here tonight (will drop to -2C tonight) so I just Polar Aligned the bolt pattern that will hold the metal pier

While standing on the North side of the bolt pattern template and using binoculars I sighted the SCP (I know exactly where it is to within a few arc min

) then carefully panned down and had my son drive a star picket into the ground at that (true south) point some 40m from the footing. Now when I sink the bolt pattern into the wet concrete during the day, I can just point the arrow that I have drawn on the template board representing the polar axis of the NJP, at the Star picket - easy!
Mike