Nighthawking Survey: version 3

Back in February there was quite a stir when the Nighthawking Survey ("Nighthawks & Nighthawking: Damage to Archaeological Sites in the UK & Crown Dependencies caused by Illegal Searching & Removal of Antiquities. Strategic Study. Final Report. Issue no. 2") commissioned by English Heritage was published (see my earlier comments, February 16, 2009). A month later, as Paul Barford observed, the report was no longer available online.

Issue no. 3, dated April 2009 is now available online. But, as Barford notes, there are significant differences. The first case study is on Icklingham in Suffolk, now sections 6.3.2-3.6 [sic.]. The second case study on Wiltshire in version 2 (6.3.8-3.9) no longer appears. Section 3.2.20 seems to have been expanded.

I cannot see a note in the text of issue no. 3 to explain the changes and differences that have been made. Barford makes a valid point:

I do not know what other changes have been made in this document, but certainly the text needs to be treated with caution. The same goes for the conclusion it draws. The way which the absence of a paper publication allows manipulation of the official record of what the Study found out ...

Why was it necessary to withdraw issue no. 2?