Who decides what is 'common sense'?
To me, a solutions-based approach would be to segregate by sex. Why does someone's so-called 'gender identity' entitle them to 'live as a woman' in jail?
Unless anyone has a better definition (and I'll happily listen to it if so - after eating my hat), it seems to me that 'gender identity' is about a feeling and a perception of what a female lifestyle might be. It is a preference in clothing, hairstyle, make-up and so on. I can't see how anyone can expect those things to be relevant in the setting of a prison.
People are entitled to basic accommodation, and 'lifestyle' is also pared back to encompass a basic but humane standard of living. Food, exercise and a certain level of entertainment are provided, but those things are the same for men and women. AFAIK we don't have conjugal visits in UK prisons, although I'm prepared to be corrected on that - a preference for a sex life is not usually accommodated, and that is a far more universal and basic human need than the right to be called 'she' and wear a dress. People whose lifestyle involved using drugs and alcohol have to forego that when in jail, even when it causes them physical discomfort. Mothers are only allowed to have their babies with them if there is a place in a unit, and if their sentence is short.
Why is a trans lifestyle seen as fundamental when so many other basic facets of life are not?