I've lived in London for almost six years and have had some real nightmare landlords and letting agencies. Once, my flat on Holland Road got flooded and the agency simply put new floorboards over it. I later found out they did it every couple years, when the basement flat got flooded. Not shocked that the whole place smelled damp all the time.
Because finding property in London's a freakish nightmare from which there's no espace, we often have to compromise something. Certainly, you won't rent a seemingly decent flat that you can actually afford just because your landlord's a total sadist.
So, instead, there's this site where you can complain, vent and share pictures when your landlord screws you. Talking about it helps.