DS who is now 21 months, went through a phase a few moths ago of slamming his head against walls, spectacular tantrums, headbutting, hitting etc. I would tell him it was wrong, and then ignore him until he'd calm down, or I'd try & distract him. It seemed to be a short phase, and for the last months he's been fine, apart from a lot of tantrums.
This last couple of weeks however, has been impossible. He's being really violent, hitting, pinching, biting, headbutting, whenever I try & tell him no, when he's doing something wrong. He laughs when he's doing it, so I'm sure he KNOWS that it's wrong. He's doing it to all his grandparents and his dad, and he's besotted with them all.
Do I tell him no, then put him down and walk away? I'm reading Jo Frosts toddler book, but she says to only use things like the naughty step when theyre two and a half.
I really am at a loss as to what to do. I feel like he's out of control, an Im not doing the right things to stop him 
At the end of November, DS & I moved back into my mums, and he stayed for a week at his dads while I was moving everything, so Im wondering is this a delayed reaction to the move? He's also been poorly on & of with various viruses erc, and I've probably been a bit softer on him while he's been I'll.
Any advice would be greatly appreciated! I'm at a loss at to what to do, and I don't want it getting any worse!
Sorry of this doesn't make much sense, I'm on my phone so can't go back & check what I've written!