If his fleet policy covers cars he doesn't own, the normal procedure is for the policyholder to contact his insurer in advance and give them the details of the car that is to be temporarily covered. With no beneficial interest there probably was no cover under his policy anyway, but your own insurance was in place so that isn't a big issue.

I don't actually have a problem with this but you found and used a loophole that may or may not be legal. If the price of doing that is a couple of extra keepers on the logbook, then that's the price.