CharlieG My neighbours re-homed a Beauceron that had originally been with a French hippy family. (I'd never heard of the breed before.) The hippies got rid of him when he killed a deer. He was great if he knew you, but a bit of a nutcase if he didn't. He was a very powerful dog with a very strong herding instinct, and very protective of his owners. If he saw a jogger, he would chase them down to leave them in a petrified state, and loved rounding up small children. My neighbours couldn't keep control of him even on a short lead.
They did their best, employing an ex-army dog handler, who proudly boasted he had never met a dog he couldn't train. The trainer eventually gave up.
My neighbours were heart-broken when they had to return him to the re-homing charity. On the up-side he was very successfully re-homed at a home for retired people. The residents love him. It appears that he particularly liked people who didn't move about too much.