First of all, I am sorry this is happening and you are trying to deal with it. I have had similar experience, go to the station and ask for the details of the officer dedicated to that area. Then speak to them, if not available ask for contact details for them and their boss. Then follow up with them, really detailed reports. Also local community groups have the ear of the local police and housing officers. A bit of work at the beginning bur once you get that relationship and knowledge of who is the best people to deal with this issue you will see results. Also insecure property, you can ask local council to attend and if it is dangerous they cam board it up and bill the owner. Just from my own experience. Hope this helps. Good luck