Well, I went for it and didn't QUITE make it but tried to make up for it...
I set up for W9D1 (4x10-minute jogs, 1-minute walks). Too many things barking at me in the 4th interval so I took a break, walked a few minutes and resumed. Altogether I did about 6km in the intervals, totalling 7.7km with the warmup, cooldown and the extra break in the middle.
I know everything I did wrong. Ran too early after eating a sandwich (was trying, successfully, to beat the incoming rain), didn't drink enough water during the day and wasn't exactly eating the right things. I was running out of gas, getting a cramp in my side and feeling a little nauseous. I'll be far better prepared on my next attempt Sunday.