Satisfied customer update:
Now on day 17 of the programme, although it's been about 23 days since I started it, with rest days and other stuff.
On January 24th I tried 100m wind sprints and managed 3 in a row before I had to lie down, and did singles with static rest in between, up to about 15x100m. Today I opted for a little St. Valentine's day massacre and tried them again, and went for 8 straight sprints with jogging rest, stopped for a minute to get some breath, then carried on with the other 2. Finished the 5x50m, then went and did another 10x100m for a laugh.
Not sure how 100m sprints measure up for indicating anaerobic conditioning (although I imagine they are a very good acid test), but, yeah, the system works.