Did it this afternoon - a lovely sunny one. Went along the canal towpath and mapped it at 4k afterwards. Not bad - I did manage to keep running all the time! The sore heel was actually fine; what did happen was that my left calf became sore after about 20 minutes. I kept going- it's still a bit sore, I reckon I landed a bit awkwardly on a tree root or stone. But I'm pleased and proud that I've done it - now for the next set of podcasts!