I rode this year, came down from York on the 15:31 train and headed up to London Fields, arriving around 6pm.
Decided to set off pretty much straight away, as I was intending to carry on as a 300km DIYxGPS to Sheringham on the North Norfolk coast. The route I took was pretty much the "official" route, with some detours where local information had indicated road works, etc. Along the way I chatted to a couple of fellow audaxers and quite a few others. Given the tailwind, I made very good time and wound up at Dunwich beach just before 4:15am!
That is by far the fastest I have ridden the Dynamo, the tailwind definitely helped.
After a brief rest and some food and drink, I set off for the next leg to Beccles (Scottish restaurant, as there is nowt else open that side of Norwich at 6am - and that's another branch of the same chain!) Whilst having breakfast no.2, I perused the weather forecast and took the executive decision that 40mph+ crosswinds and a tired rider were not compatible, especially as my torn rotator cuff is not totally healed yet, so diverted to Hoveton & Wroxham station for the train to Sheringham. A wise decision, listening to the wind at the moment!
Total distance for the Dun Run & extras: 250km, plus 6 and a bit from Kings Cross and 4 and a bit from home to York station. Still happy with that!