There seems to be a nuance (which is missing from the title).
The initial paragraph refers to activities which are prohibited.
Peers agreed by a majority of one to ban videos and images depicting
relationships that would not be allowed in real life.
There's perhaps a little more nuance (sexual activity with a step- partner has as an age of consent of 18, rather than the more-typical age of consent of 16)
They also agreed to bring intimate pictures and videos of adults
pretending to be children in line with similar images of real children.