The name rings a bell but I can't help really.
The article on sexism in the education system (without calling it that) is pretty good, and some of the other posts are on more general gender equality, but most of the sections show its really a trans rights trust - or that is the principle area of interest.
The glossary of concepts is a bit more straight forward on what sex is, and the distinction with gender, than some similar glossaries, but it still doesn't really get to the heart of what 'a gender' or someone's gender, actually is.