Pete sent me the plan of the stone numbers - so I can refer to them by id. It's very odd looking at a site from afar - via these and other archived images. I also have a little copy of Thom's plan which I hope is the 'definitive' version. I thought these stones were among the oldest parts !

Thom mentions just one azimuth with the Great Circle and it is the northerly direction between the two inner circle centres. He attributes this possibly to the setting point on the horizon of Deneb at about BC2000. I would suggest that the shorter section of the Z-feature - the few stones nearest to the southern entrance - actually describes this same azimuth (which is also found in other monuments such as Seascale and Smithills).

There is a theory that the native south americans couldn't perceive the wooden ships of the conquistadores. They just didn't see them coming. It is odd how the shared viewpoints of a monument closely agree. (This means I can find any number of internet images of the Z-feature slantways on and absolutely none taken behind the chapel wall looking over the top of the longer section).