You can choose whether to use male, female, or gender diverse, just the same way you can choose ethnicity - with no supporting documentation. You do not need to change your birth certificate or other ID to changer your gender marker with MSD.
Tag: WINZ
Voice Therapy Funding
Any trans person can get funding for voice therapy through WINZ. They don't have to be on welfare to get the disability allowance or child disability allowance as it's not income tested.