Agree with Brokendaughter. We take what crumbs we can - and this is a loaf of bread in those (metaphorical) terms! - but I actually think it's pretty damning that they are virtue-signalling their acknowledgement that mixed changing rooms are unsafe through the carefully disingenuous change to "women" only.
Isn't it the height of hypocrisy to say, "We recognise that men may exploit mixed areas and this may make women unsafe, so we'll remove the explicitly mixed area in favour of one that we will, instead, carefully imply IS single-sex, when it actually WON'T be," (because how else to interpret the deafening silence in response to endless tweets from concerned women asking The Question, when other tweets have received rapid, courteous responses?)
Primark, have the courage of your convictions. Either you believe in including transwomen (presumably, of necessity, on the basis of self-declaration), or you remain content to exclude those women for whom your failure to define "woman" is a deal-breaker - the significant proportion of traumatised, religious,
young, disabled and simply understandably cautious females who may continue to feel - be - unsafe in your changing rooms as long as you ignore this question.
Politicians, take note. The question "What is a woman," may be used as a petty "gotcha" in some contexts, but, in situations like this, the answer determines which public spaces some women feel able to access.
I'm not saying what I think the better answer is here, but that the absence of any answer is disrespectful and hypocritical, showing a cowardly disdain for both transwomen and females - but arguably rather more the latter, in a culture in which "woman" is now more commonly understood to include the former.