I've just read the UK Government Online Safety Act guide and the impression I get (as someone who is not a lawyer) is that Mumsnet could very well be classed as a service to which it applies. Mumsnet is an online forum on which content that could be seen as harmful for children - eg discussions of sex acts, eating disorders, self-harm, suicide etc - is available. And as far as I can see, Mumsnet does not do any age verification to ensure that such content is restricted to adults who are consenting to see it.
Can I ask what advice Mumsnet has received about its responsibilities under this act and if there is the likelihood that either Mumsnet is going to either be much more rigorous about its content moderation, and/or the introduction of age-verification technology for Mumsnet posters?