Looks like your HR was gradually going down (weight loss winning over other factors perhaps) before the monitor went mad. You really did bomb down the hill at the start! Once again - great run!
Cheers Kevin! (I'm new here, forgive me if I don't get the etiquette immediately.) Gosh I hadn't noticed the HR drifting subtly down, you're right. As for mile 3 -- downhill 'loping' is a speciality now, but I'm just a one-trick pony!