In reply to Lemony:
Hey there, what a sh*t situation with your neighbours. Unless you are exaggerating this, and I don't think you are, it sounds worthy of some action. I wouldn't recommend speaking to your neighbours, you only know them to say hi in the passing so how you go from that to "we hear you screaming at your kids and worry about them" is too big a leap with many risks. As another social worker, I've been saddened when something terrible happens and all these neighbours and relatives come out of the woodwork to say that they had seen it coming, and I think, well why didn't you bloody do something. As a member of the public, your responsibility for these children ends with you speaking to the authorities, then it's up to them to do their jobs properly. The authorities most likely won't tell you what happens afterwards, but don't let that worry you, you'll have done your bit. Everybody ought to feel that they can speak up for children in their community, because they're all our children and they'll pay our pensions when we're old and retired.
Finally, I grew up in a house where we three kids were thumped by our parents, and next door was a house where the mum shouted and swore non stop at her children, but they were never hit. Even though you hear this horrible stuff, you don't really know what's going on in there, and your imagination might be far worse than reality, but it might not. Tell someone in authority. That's the local social services office during work time and the 24 hour team if at weekends or at night-time, you'll get the numbers off the internet. The NSPCC helpline is another option, and if you live in Scotland, speak to the local children's reporter's office. You can contact all of these people anonymously, they will press you to give your name, but there is No reason to give this, even if they say that it's an important identifying factor in the evidence chain if they do find evidence of crimes. You do not need to identify yourself.
All the best.
Tom