In reply to Edshakey:
I plotted Damian Hall's split times against John Kelly's and JK was consistently faster from the start (it's an almost linear increase) until Airton, where he was 4 hours ahead of Damian's time. From then on the splits are very similar, meaning they both ran the end of the route at the same speed, until the final stretch from the Snake Pass to Edale.
Unfortunately they don't have the same timing locations on the tracker for this last part, but despite what seemed like a fast finish by JK, Damian actually ran this part 25 minutes quicker.