The next stage was a more intensive augering survey, undertaken by Birmingham Archaeology in 2006–7, following a series of transects across the alluvial areas which were associated with fen names. This was intentionally carried out without the location of the known peat deposit being released to the survey team, to provide a check on the effectiveness of our sampling methodology. The value of this check was confirmed when the work failed to locate any peat deposit. This showed that any such deposits were likely to be far more restricted in extent than previously expected and that more intensive survey would be required to find them. But first the palaeo-environmental team were directed to the known peat deposit, in Fen Meadow, to enable a series of samples to be taken for detailed analysis – first pollen analysis and then radiocarbon dating.

From late 2006 to early 2008 the attention of the battlefield survey focused on the zone surrounding Fen Meadow, because the initial pollen analysis suggested a wetland here which continued well into the medieval period. It appeared likely that we had located the ‘marsh’ mentioned in the battle accounts – exactly where Foss had predicted. It was not until the radiocarbon dates finally arrived that it was realised that the upper level of the peat was in fact of late prehistoric date. However, uncertainty remained due to the confused nature of the upper boundary of the peat. Given this and because, at that time, no other substantial peat deposit had been located elsewhere, a more detailed sampling was requested for Fen Meadow. This was undertaken using machine dug trenches, enabling the sections to be examined and large column samples taken at carefully selected points on this section (Figures 4.3 & 4.4). This revealed that there had been some erosion of the peat prior to the deposition of alluvial cover. The new sampling and more sophisticated analysis yielded a later date, but still only of c. AD 700. Again a discontinuity at the upper level of the peat was noted but, given the deep alluvial deposit above this, it was argued that the wetland had disappeared long before 1485.⁷