My 3yr old DD is a headbanger. This has been going on since she was 9 months old. I have seen my health visitor and my GP numerous times, yet they wouldn't refer DD to a paediatric consultant until she was 3, apparently the majority of DC who do headbang grow out of it by their 3rd birthday, and this is why they don't refer until after the 3rd birthday. I was advised to ignore the headbanging as much as possible, since health visitor and GP both agreed DD was probably doing it to get my attention or get something she wants. The HV and GP explained to me that although it looks violent, DD is not harming herself.
Unfortunately, I cannot ignore the behaviour because, apart from the dreadful noise, the neighbours bang very long and very loudly on the adjoining wall if they hear any noises including banging going on in my house. They bang so hard, my walls and floor vibrate. 
I have spoken to the neighbour and explained that DD is headbanging, that I am very sorry and that I am doing everything I can to stop it happening. I explained that DD has seen GP's and HV but they wont refer her on until she is 3. Neighbour agreed there wasn't much more I can do. (This was a while ago.)
Instead of ignoring, I quietly remove DD from wherever she is banging, and put her on a bean bag or I try to distract her.(Told neighbour this too) DD very quickly goes back to banging again, so I can be picking her up and removing her up to 60 times a day.
The neighbours have continued banging every time they hear DD banging. DD doesn't bang for more than a few seconds before I have removed her from wherever she is banging, so it is those few seconds of banging that makes neighbours bang back for a good 30 seconds. Neighbours have banged so long and so loud that DD has wet herself because she was so frightened. The main culprits who are banging apart from my DD are the 2 sons living next door, one is 20 and the other is 17. The mother of these men next door has told me that she has had to restrain her eldest from coming to my house to have a go at me over the banging. 
When DD was 3, I went back to my health visitor, who referred DD to a community paediatrician. Community paediatrician has told me to continue distracting, removing, and not making a fuss. I have explained to community paediatrician that I cannot ignore because of the trouble it causes with my neighbours, so I have to continue with the distracting/removing. Community paediatrician reassured me that DD will grow out of it, although she doesn't know when.
DD only ever bangs during the daytime, she sleeps all night. I know that is no consolation for the neighbours and I do understand why they are annoyed, but I do not know what to do next.
I feel it is all a little unfair tbh. Next door bang their front door shut (no it is not stiff) every night, as an example..last night they banged their front door shut between 8-11pm at least 30 times. They have also been drilling every night this week after DD has gone to bed. (After 8 pm). DD is a light sleeper, and I think this is inconsiderate, but I don't start hammering on the walls, I just grit my teeth and ignore.
I have even kept quiet while the eldest DC next door was honking his car horn long and loud outside the house at 11.20 pm the other week. 
I am just getting really fucked off with the audacity of them to hammer on the walls when they could knock at my door and discuss politely, instead of trying to intimidate or frighten my DD and I, as well as continuing to make all the noise they do without a single thought for us. (Shouldn't both neighbours try to consider the others, instead of one doing as they please and the other running their lives around what will or will not piss their neighbours off?) My eldest DC wouldn't dream of hammering on anyone's wall. I have known the men that live next door since they were born, yet not always lived next door to them, and I feel like I am being bullied by them.
My life seems to revolve around keeping the neighbours happy, yet they have no consideration at all.
So AIBU to want to go round their and have a rant at them and ask them wtf they want me to do to stop them banging on my bloody walls, even though I am not comfortable with appeasing bullies? 