Oh my gosh, what a stunning horse
Ground driving is absolutely fantastic. I don't know of many english trainers who even do it anymore, but I know I start off all my youngsters with ground lines. That's how I can get the "woah" and my turns figure out before I get on and start riding.
Having those lines also helps desensitize them to a lot of things. I absolutely love ground lines, I really do.
Those were great photos.