Hi, I’d like advice please. My neighbour has built a one story extension . The rainwater is pouring into my flatroof because they have taken off the main houses downpipe. They say it is running down over their new one story roof into their new guttering. It isn’t it’s running along the grooves of their new roof tiles into my flat roof. I have asked them nicely to fix it and allowed them to get into my flat roof to rectify it.?I am being ignored. We usually get on so I don’t know why such an easy job is becoming an issue . It’s upsetting me as I’m on my own and don’t know what the rules are.