I should imagine the weekend was the best time to start as more pacers and helpers are available.It also conicided with the start of the Fission race and would allow more publicity for his sponsors.
Other walkers shouldn't be a problem,other than in Teesdale and parts of Hadrian's Wall.
His time is very impressive,far better than I expected,and if he keeps going at this pace he might beat the record.Still a long way to go though and Joss Naylor slowed during the final 10 miles on his N-S attempt in 1973 and failed to break the three day barrier.