Alan B,

<<Finally, those in public office must assuredly, be mentally competent!>>

Are you saying you know for sure that Fred Nile in his 86th year is mentally incompetent? Or, do you disagree with his Christian worldview so he gets a label of mental incompetence by you?

Fred Nile, although meaning well is too old.
All the potential aspirants for succession in executive positions in the Christian Democratic Party have long since given up and my guess is that this political party will disappear once Fred retires or passes away.
Joan Anderson made his reputation as a Christian believer and advocate in the Federal sphere, and wisely resigned in middle age. He continues to comment on various moral and ethical issues via his Internet site, and social media posts.
In my opinion, politics (both State and Federal) should be the domain of middle age people, both male and female. They should have the sense to quit in late middle age. In Australian politics, most lose endorsement as they age, and are succeeded by younger candidates. In spite of what some say, no one (even senior politicians) is indispensable.