He's been like this since he was 4-6 months, pinching and deliberately slapping people in their face - particularly people with glasses knocking them off.
It's not a motor problem, can line up cars perfectly without an issue. Doesn't do well with duplo, can put the bricks together but prefers throwing them everywhere.
"No" doesn't seem to be working, I've heard the "its a stage he'll grow out of it" - but at two years old, its now turned into biting too!
None of the other children who are older have ever been like this.