Thread: new cat pooing on the floor! Help

A long shot but could the other cats be bullying her on the toilet perhaps?
I am reading this book at the moment by a cat psychologists and she tells stories of different peoples problems with their cats and how she helped solve the issue. One of the stories was one cat had a problem on the toilet and the owner had moved it etc, cleaned but it turned out that the other cats didnt like her using it and would bully her when she was going which in turn scared her to go near it, so they bought a second litter tray and bingo no more accidents and happy kitty.