So, I did it. One 5.37k lap of Arthur's Seat in 38:29. The 5k bit was 36:17.
The conditions were idea, the participants (all 2,500) we're amazing and the support at the finish from the well wishers and early finishers was brilliant.
It was never going to be my fastest time given an ascent of 89m for the first half of the run, but I'm still chuffed to have done it and for the money raised so far.