Running 58:47  12.62 km (4:39 / km) +113m 4:27 / km
So I've made it to page 120 of my running form book and it is rather frustrating. While it's readable enough, it doesn't offer much practical advice so you're left hanging a bit.
Having said that, it did mention 'tripod foot landing' (i.e., full foot, not heel or ball) and aiming for 'tall and bouncy', so I tried that out on a park loop in the gloomy evening drizzle.
Overall it worked rather well, mostly because it made me focus on my form more generally - I noticed (and tried to correct) my shoulders droop and my arms flail about in the second half when I got tired. I need to do more shoulder strength work as it was tough keeping the arms working throughout.
As a bonus, focusing on form passes the time more quickly. So a step in the right direction and the right trade-off between speed and endurance.