Tried the 6k again tonight, no problems at all. In fact didn’t feel anything in my foot where the glass splinter went in from the moment I removed it.
One interesting thing tonight was the fact that it had been raining and much of my run was on greasy paving stones. I’ve mentioned before that you’re really not supposed to push off with your feet, rather lift them, driving with the glutes instead. So having the ground underfoot slippery really makes you aware if you’ve a tendency to do this or not. Either way it’s good training for form, which as regular readers should know is everything in running, shod or barefoot.