Set off on W4R1, then realised I had messed up my loo schedule and hadn't peed in 90 minutes. I drink a lot of water and tea, so that's a long time. Worrying about needing to pee kept my mind off the running, which went well, and I then snuck into a university hall of residence to use the facilities.
I did notice that a young guy overtook me at a brisk walk when I was running. I actually think that I also walk faster than I run. Oh well, plenty of time for speed.