Thanks for posting that MelMel - interesting indeed. There is a forum topic running at present about Jim Leary's/David Field's recently published book on Silbury. Perhaps you could post this link there too so it doesn't get missed.
I found the findings by Jim Leary/David Field that Silbury was an ongoing process rather than the three separate stages as suggested by Prof Atkinson in the late 60's, rather welcoming. What I didn't agree with however because I see no evidence for it was that they believed there was no set plan or blueprint as I feel that rather odd for such a major work of construction. My personal view after many many years of research is that Silbury Hill was just one part of a planned and organised earth figure that was so big that it couldn't possibly be built in the lifetime of one generation so it was built in the continuing stages as suggested so that each generation could benefit from the rewards it supposedly offered the people of its time. To give a clue to this one must 'think neolithic' and have a belief in the Afterlife. The remaining man-made component parts of the figure would also have been built in an ongoing way with a good example being timber posts replaced by stone as time progressed. Many of these other component parts were what we know today as the Avebury Complex...but not all of them! A review of my work can be read here http://networkedblogs.com/a047Z