MattC and I rode this yesterday (2nd Jan), eventually making it round in 13.5 hours... (just inside time, I think). Weather was good (sunny, light wind), but the roads were icy in places which made for a rather nervous ride. We both came down just before Lechlade on a mahoosif sheet of ice from field run-off. No major injuries, but no confidence in the road afterwards! If there had been a station in Lechlade, we'd both have been on the train!
After Lechlade (and sunset), we re-routed onto main roads (A361, A40 and A44) to avoid the ice. Longer route, but definitely quicker given the conditions (and ice free). The crawl down to Gt Barrington to get the info was 'fun'...
Pleased we finished, but overall, with hindsight, probably shouldn't have bothered...