I work in a large public sector institution and saw that their webpage on the Equality Act 2010 listed one of the protected characteristics as 'sex (or gender)'.
I emailed the Equality and Diversity team to ask why they had added the caveat of 'or gender', as this misrepresented the law and was confusing.
Happily got an email back stating that as the page outlines a legal definition, and the word 'gender' is not included in that piece of legislation, they will remove the reference to gender. Hooray!
(This was followed by a few fairly pointed paragraphs about how gender is a synonym for sex, also includes people's gender identity, can't tell someone's sex just from looking at them, trans women are women etc... I imagine my name is on a list somewhere now...)
Very small victories but a victory nonetheless. Sending my thanks to the posters of previous threads on here for the inspiration.