I've held off putting this on the blog as I had submitted it for inclusion in the Audax UK magazine - it has now been published in there, so here's the gory details: There's also some Strava data here:
I did it! There will not be a full blog report on this ride for a little while. As I was the first British rider to attempt one of these rides, I hope to drum up some interest in tackling these adventures with an article in Arrivée (the AUK quarterly magazine). If that gets published, I will put up a copy here.