My mum was on the phone yesterday complaining about the state of her neighbours? backyard. She?s mentioned this before but now the weather is getting warm at last she?s worried about smells, vermin etc. Basically they don?t seem to use their bin and just chuck their black bags in the yard ? they?re in a pile to the level of the window sills now and the neighbours also have a dog (which they never walk) who rips open the bags and scatters dirty nappies, leftover etc around as well as poos in the yard which they don?t clean up. It?s not pleasant to look at and I can?t imagine it will smell great either.
Neighbours are otherwise lovely according to my mum (I?ve never met them, they moved in last year and I live in a different part of the country). They have a toddler and a baby so get through a lot of nappies! Their house is apparently immaculate inside 
The yard can only be seen from the upstairs of my mum?s house and one other house across the lane so she?s worried if she called the council they?d know it was her, plus these are private houses so not sure how much power the council would have? She has mentioned it to them in passing but they just say they?re going to get it sorted and never do. They also have an old sink, a couple of old gas bottles and some mouldy boxes in the front of the house (it?s a terrace with a small area in the front walled off from the street).
Any advice?