Thanks June. I'll be tied up with layout and editing for a while yet so can't really give too much away before it's all finished, which makes it difficult for anyone to discuss the subject yet but now hope to finish it this winter.

I deliberately avoided reading Anthony Johnson's book 'Solving Stonehenge' or Nicholas Mann's 'Avebury Cosmos' until I'd finished my own calculations, so that I could genuinely compare findings. I've now read both of these and would recommend them both, particularly Anthony Johnson's since he really gets to grips with specific geometry and how it came into being.

Once you have the right centre for Avebury the geometry gives away much more information than at Stonehenge however, so it is possible to take things much further.