https://www.gov.uk/government/publications/call-for-input-incorrect-guidance-on-single-sex-spaces-and-gender-self-identification
Apparently this has not been well publicised - I cannot think why not.
This seems like a great opportunity for the marvellous GC Mumsnetters to have their voices heard. I don't believe there is anyone in the UK better informed on this subject than a reader of the Feminism: Sex and Gender board