Not that I saw but he used to shake the cot, so he might have been and he used to climb out of his cot when very tiny and we couldn't figure out how he did it, until I heard him one night and watched him, he was very ingenious.
Just a thought, we put a few toys on the side of the cot, they were like activity type things that attached to the rails and we'd hear him playing on those if he woke up. Quite a few teddies as well.
I used to panic when he was banging his head on the kitchen tiles but if I didn't rush over he would stop and look round to see why I wasn't doing.
It is upsetting to see though but if I was stopping him doing something I would offer him something else at the same time.
You mentioned that even if they take him into their bed, he still won't sleep and messes about, so he might just be awake and want to play.
I'm thinking maybe if when he starts getting frustrated in the night and he's headbanging, they could just give him say a little computer type thing and tell him to be quiet and if he starts again, take it off him and just leave him and grit their teeth. He will be better when he can tell them what he wants, he'll probably talk very early as well.
It does stop though but probably sooner than three, as he started it so young. He's probably going to be a live wire though and he's probably into everything already. Very curious! Probably very clever!