That's another good point about this campaign, rosemarble. It shouldn't be necessary, as so many PPs have rightly said, but .. this is where we find ourselves.
Giving paramedics specific training on CPR/defib procedures involving breasts may result in more women surviving cardiac events, and that's a good thing.
Even giving them the knowledge that they may encounter scenarios where a female casualty turns out to be a man with 'breasts', or a male casualty turns out to be a woman wearing a binder, and the confidence to do what has to be done without fear or hesitation, is not a bad idea.
A different heading on the page, saying 'women' not 'PWBs', would make a big difference to how it is perceived.
edited to add: if I was contacting St John Ambulance, I'd emphasise that I was objecting to the phrase PWBs, but as a woman I welcome that they are moving away from taking the male body as the norm, and more women will hopefully get the correct treatment more promptly because of this campaign.