Here is what Jan Harding said:

"The supplementary information states that "it may only be in the very Late Neolithic that the first monuments were constructed. The henges may, therefore, form part of an Early Bronze Age tradition" (Summary, 94). Much is made of this, presumably to debase Thornborough's general significance by placing it late in the sequence of monuments building across the British Isles.
This remarkable claim ignores what we do know about Thornborough and monument building nationally. Firstly, available radiocarbon dates from human bone found within the Triple Ring Ditch at Thornborough place the monument in the first half of the fourth millennium BC. How is it therefore possible to argue that the first monuments were not built until the "Very Late Neolithic", over a thousand years later? By contrast, the evidence suggests that Thornborough's 'sacred landscape' had especially early origins. Moreover, cursus monuments nationally are know to date exclusively to the latter half of the fourth millennium (Barclay & Bayliss 1999), conventionally labelled the middle Neolithic. To argue that the cursus at Thornborough is later is unconvincing special-pleading. Thirdly, the applicant dates the henges on a single radiocarbon date which I have already dismissed in print as being unreliable (Harding 2003, 107-8), whilst completely ignoring that henge building nationally is known to have ended by the final Neolithic (Harding 2003, chapter 5). Again we are expected to believe that Thornborough is the exception to an established national picture."

This was a response to Tarmac's mitigation strategy.