I DNFed at 311 km - it was actually the Northamptonshire border.
Not bad as a 3rd Audax, especially given that the last was a 300 km (Moonrakers), and I finished with 6 minutes to spare! This time, it was 18:20, so a marked improvement in pace.
I was pressing on reasonably well as far as Cambridge, although the last few miles were getting hard. No real stops, just refuelling. Then it was the dash to St Ives, and I couldn't really slouch on that bit. Especially since it was an adventure navigating the road closure without using the A14 (we ignored the closure, and were creative with what tarmac was present!)
After St Ives, I was really suffering. I set myself an objective of getting as far as 30 km to go to Northampton, my sleep stop, with a group. I figured I'd be able to face 30 km alone. However, I had to drop back at 35 km to go, so halfway between Ives and N'Hampton. And at the pace I was down to, I really couldn't face 3 hours of grovelling along the road, so I bailed.
https://www.strava.com/activities/2964494102