The 2009 documentary is streaming now on Prime. Watched it tonight as I remember watching them all. Really insightful and the young boys in it is so lovely too.
It also shows John telling his Labrador in a tic to cross the road. She doesn’t. She clearly knows when he’s ticcing vs when he means it, and when he says “go” in a tic she just sits obediently. Dogs are bloody awesome.