"Irrespective of whether this support's GH's position (which it doesn't - his hypotheses are quite clearly laid out in his various books and he is NOT talking about longhouses and log pallisades) ..."
Correct, and let's remember that the existence (and age) of theses neolithic circular enclosures has been known for more than fifteen years. The first comprehensive analysis, published by Gerhard Trnka in 1991 -- years before Graham Hancock published his books -- discusses dozens of these megadendric structures.
"... there are fundamental problems with this - the main thing being that the whole thing is unpublished, in a formal sense."
This is not quite correct. The German and Austrian archaeologists who have been discovering, excavating and analysing these structures for more than a decade have published dozens of scientific articles; they have organised international conferences; and they have produced multimedia exhibitions that present their results and hypotheses. Therefore, they were not amused when The Independent told them that the "discovery" of these 150 structures, supposedly "revealed today by The Independent," will "revolutionise the study of prehistoric Europe." All the discoveries were revealed in public, and the so-called revolution took place many years ago.
"The second is this notion of 150 sites being precisely dated; given archaeological financing is anybody seriously suggesting that all of these sites have been fully excavated over the last few years? Or are they basing this on a few excavations couples with aerial surveys, etc.?"
I don't know how many of these structures have been fully excavated and dated. I think that Lower Austria has more than 40 circular enclosures, and as far as I know, roughly 20% of these structures have been excavated.
"That aside, there's asomething intersting here - if there WAS a sudden collapse around 4700 BC then that would fall nicely into the sudden climate changes occuring at the time."
Well, the possible reasons for the rapid disappearance of this phenomenon are certainly interesting, but then again, we don't even know the reasons for the sudden appearance of the phenomenon. Most archaeologists who have analysed these vast structures admit that they have no idea why they were built in the first place.
Michael