I have a neighbour who obviously is suffering with a mental illness. She constantly comes in and out of her front door, bangs on the door and screams and shouts every night. I have reported her to social services and she is well known to them but they are not doing anything. I have rang noise nuisance at the local authority to be told they have to witness it. Its not constant but stops and starts most nights into the early hours. Catching her doing it would be difficult. I could try to record her but the Council said no.
You might not be doing the right thing by video recording her on her own property. Could you ask them whether they will accept audio recordings, for example using the noise app. Failing that, the EH department can provide you with a recording device and install it at your house. They can also come to visit you and spend some time in your house in order to witness it (this might involve one or two appointments outside their usual out-of-hours service). If your neighbour has mental health issues it is a shame but not a reason for the issue to be ignored or not responded to. Does she have a social housing landlord? If so you can contact them too – social housing providers have a duty to respond. Whichever agency takes the lead on this they will probably wish to liaise with social or health-care services in order to come up with a suitable solution.