Not sure exactly how much the drainage / rain vs pre em damage is to blame, but I think these are the worst headlands we've had since even before 2019. Much worse than I was expecting. First drilled block around 1 Oct is absolutely fine by comparison.

Update to this. Contacted the author and he had not realised we had a few other wild bird seed mix fields just outside his study area. His heart-warming response detailing just how much good these stewardship plots are doing atm (few details redacted to protect others' info):

Recently bought 4 Agrolog grain monitoring probes to try. They look really nifty and a must-add to the list of FETF items, Jonathan Baker. Nicely modular and flexible. Set up in 5 minutes and really nice remote monitoring app. Decent explainer video on YouTube.