This just made me laugh...

I stumbled across a race report from last year... UK Ironman 70.3.  And saw the run stats.  They made me giggle a bit.  Check the average and moving paces.

UK Ironman 70.3, 21km run, last year...

London Ultra, 51km run, this year...

OK, there's less than twice the elevation gain in over twice the distance, and yes the 70.3 had the small matter of a 1.9km swim and a 90km bike ride first, but golly-gosh that's a small difference in pace between the two.  And I was holding it back in the Ultra, to conserve carbohydrate stores/stay under the knee-point in the fuel burn graph.  I -think- I might just be a bit faster this year.