Consent Form 1229 - Child migration to Oz

I read with interest Wazza’s recent thread regarding getting the father to agree to the child migrating to Australia. I am in the process of sponsoring my wife’s two sons to Australia and after reading this thread I am a little unsure whether or not I need to get the fathers permission. I have the consent form 1229 in front of me now and it states;

“Where children under 18 years of age intend to travel to Australia, their non-accompanying parent(s) or person(s) with parental responsibility (anyone who can lawfully determine where the child/children is/are to live) may be required to sign a consent form to give permission for the child/children to be granted an Australian visa for the purpose of travel to stay temporarily or permanently in Australia. If one parent, or person(s) with parental responsibility, has lawfully been made solely responsible for making decisions as to where the child/children is/are to live, then only that parent or person needs to sign the consent form”.

At my wife’s divorce proceedings she was granted sole custody of the children. My interpretation of the last part of the above paragraph is that only my wife needs to sign the 1229 consent form. I would also add that the children recently holidayed in Australia and on that occasion my wife completed the 1229 form; we did not seek permission from the father nor did the Australian Embassy request permission from him. Any feedback from people who have had experience in this area would be greatly appreciated.