Transwomen offenders don't belong in womens prisons. Firstly because such a high proportion of TW offenders are convicted sex offenders. Secondly, because a thumping majority of women in prison have been victims of male violence, and their right to live in a safe and decent environment has to trump the feelings of one or two male prisoners, no matter how strong those feelings may be.
Transwomen prisoners are kept safe in the male estate. The vast majority of them live on Vulnerable Prisoner wings, or in designated sex offender prisons. This concentration of TW prisoners can cause its own set of problems, but they don't affect or concern women prisoners.
Transmen are suitably kept in the female estate, and I can't ever see that changing. Noone would want to sign off the board that put a transman into the male estate and they turn up brutally raped. You may well ask why the same reasoning that won't put transmen into the male estate can't be applied to prevent transwomen even being considered for the female estate...