I've not spotted another thread on this, but I've just been made aware that the Office for Statistics Regulation has finally produced new guidance on how producers of official statistics should collect and report data about sex.
I've not read it in full yet...what I have read makes clear arguments about the need to ensure clarity around the use of terms (it doesn't provide standard definitions, but includes the interpretation of terms that they use, which I think seem clear), that sex and gender shouldn't be used interchangeably and that Sex is a protected characteristic.
I'll have a more detailed look later, but the one concern I have is that while it talks about ensuring the right response options are available (e.g. it talks about gender identity options including non-binary or whatever), it doesn't include anything mention of ensuring response options are available to cover those who don't believe in gender ideology/don't have a gender identity. In my view, any data collection which fails to provide response options which accurately reflect this means that factually incorrect data will be collected about some individuals, and this would be in contravention of the GPDR principle of accuracy (and will also undermine the quality of the resulting data).
There is an email address for feedback, so once I've read it all I'll send some in.
Collecting and reporting data about sex and gender identity in official statistics: A guide for official statistics producers – Office for Statistics Regulation (statisticsauthority.gov.uk)