Hi Hoppy, isn't it strange about stamina, it doesn't seem related to how our knees recovery is going.
My knee has been up for walking for many weeks, but tiredness was the problem. Then suddenly, about 2 weeks ago, it was as if someone pressed a switch and my energy returned. Walking miles now, and really enjoying it, as are the dogs.
I wish Beachy Head was just down the road from me, I'd be up there all the time.