Request #305 From Gary

Okay, been looking for this for ages and any help is appreciated. YA science fiction book from late 70s, I think the cover was black. Set in a near future where a rebellious boy is sent off to a school in the middle of nowhere, possibly in Scotland. He escapes and befriends a war robot named Ogre or Orcus or some such. There’s a scene earlier where the kid attends a show at an arena where the robot devastates a number of cars.  It’s NOT “The Iron Giant”; I know that book well, and the one I’m looking for is a novel, not a storybook. I did find it briefly in 1989 or so but forgot about it again. Any help very welcome