Whoo, experiment finally worked! Now just have to repeat it 3-4 times over the next few days and hope it holds.
Just made it to Cross Fit in time for another partner workout. 10 minutes of burpees in turn, starting on one each and increasing by one each time, then ten minutes of kettle bell swings in the same vein. I beasted Isabel on the burpees and she ensured I was thoroughly destroyed on the kettle bell swings. Good team!