The emphasis has been on how women are defined. The current question though, and the one the Government are currently consulting on, is who should legally be considered a woman.
It would be interesting to understand how babysharkmother, Ocado and other describe "trans" and hence "transphobic". For starters the Stonewall definition is:
Trans people may describe themselves using one or more of a wide variety of terms, including (but not limited to) transgender, transsexual, gender-queer (GQ), gender-fluid, non-binary, gender-variant, crossdresser, genderless, agender, nongender, third gender, two-spirit, bi-gender, trans man, trans woman,trans masculine, trans feminine and neutrois.
Many reasonable people are OK with the idea that those with those with genuine, professionally diagnosed, gender dysphoria might in many/all situations be considered as women. However quite a lot of people will struggle with the idea that anyone on the Stonewall list above would be able to self-ID as a woman to gain access to women's protected spaces such as prisons (Ian Huntley apparently now identifies as a woman ffs), womens refuges, Girl Guides and so on.
For whatever reason though, people like Ocado and babysharkmother seem to want to shut down through denial or insults. This is is a huge topic for society, and one that needs to be debated. Even on a small scale, for every transgirl who might join the Guides, there will be lot of girls wanting female only spaces (those from conservative communities, teenagers who are not body confident to share sleeping spaces with male bodied peers, victims of abuse etc) who don't. It really is not for a food delivery service to occupy a moral high ground, deny the dictionary definition of women, and to try to shut down the debate.
The Government consultation is here
www.gov.uk/government/consultations/reform-of-the-gender-recognition-act-2004