At 8.15pm the foxes reappeared down the track and were joined by a third fox, the other parent, possibly the male as he is bigger than the female. This one also has a bushier tail. The adult foxes seemed to be playing with the cub chasing each other. Eventually they disappeared again.
9.10pm and the foxes were visible in the gloom. Now the adults were actively hunting. The cub was investigating things but more, it seemed, out of curiosity. The cub came down to within about 10 feet of where I was standing at our wall. The fox eventually lay down on the track looking out towards the road. Then it sat up. I took the chance of taking a photograph using flash.
It did not seem to disturb the fox at all. I watched it for about another 10 minutes before it trotted back up the track. When I went back into the house, I could still see the shapes of hunting foxes in the track.