At 6:05 it was still murky and felt cold so I opted for my dayglo (now slightly faded) yellow Nike Go Nocturnal Run London long sleeved top. Went for the standard anti-clockwise loop of Lea Valley Walk north to the big hill, over the top and then back down the Luton Road to Harpenden.
Took it generally easy, although had to push in a bit towards the end when I realised I was at risk of getting back late. In the end I was late and not wanting to sacrifice breakfast ended up catching a later train (standing room only) but still made it to the training course on time.
The path from Harpenden to Cooters End Lane is now 95% tarmac and a viable route for road bikes. Unfortunately the section behind the sewage works is still not great - OK for running or perhaps a mountain bike if you don't mind the steps but a no-go for roadies. Can but hope that the funding to complete the missing link comes through soon.