Have you ever noticed an Eastern facing arc there at all, by any chance ?
I couldn't see one in the pics.
Dave1982
Sorry if the question seems obvious, but do you mean an arc of circle stones at the east? if so then yes. There is a good plan on the pdf.
No, I meant an arc of stones, that faces East. I couldn't see one of the PDF but thought if you are familiar with the site you might have noticed one ?