head banging

hi ladies, i wonder if u can help...ds isn't one for big tantrums as such, but he's developed this thing where if he's in a bad mood/over tired and gets told off/told no, he bangs his head on the floor/wall, sometimes just once, sometimes several times, and sometimes he does it really hard, i try to ignore it in hope that as he's not getting a reaction he'll stop, but it's been going on for months now, and of course if he does it really hard i just can't ignore it as it's so hard that i need to check he's ok and tell him not to do that...he used to do it, ages ago, but ignnored it and after a couple of weeks he stopped, but since we moved house in novemeber he started again, and don't think it's been helped with the arrival of his sister in december



any ideas to get him to stop, as i'm worried that's gonna do some real damage to himself



thanks xx



Austin 23months, Phoebe 10weeks