If you have a child from a past relationship, then the other parent needs to consent to the child coming to Australia.
If they do not consent, then Court Orders are required, unless the other parent has disappeared and cannot be found.
If you have any custody issues, then you should engage a migration lawyer with family law experience to work through the custody issues.
The Migration Place is a division of Irish Bentley Lawyers, and we are experienced in migration law (over ten years), family law (over 20 years), and cross border Court work.
We have been engaged by local Councils in England to assist the UK migration of adopted orphans and have worked with a number of UK and Irish Family Firms to solve custody issues, and get the visas through.