"¶¶¶ Nuclear Figures Don't Add Up ¶¶¶"
We didn't help the Brits to build theirs; we only provided a test site. We did not and do not have detailed weapons designs or the weapons themselves; the Brits refused to supply this to Menzies when he asked.
Australia could build a fission plant from the ground-up. That's about half the reason we have Lucas Heights, as it maintains a base knowledge of nuclear technology - the other half is production of medical radio-isotopes. The time it would take would depend upon how much help we got, probably a few years. Weaponising it so it was small enough and reliable enough to be mounted in a F111 or F18 would take longer. Its not clear that India has done this yet (though Pakistan probably has).
Australia doesn't need nuclear weapons to be "safe" from Indonesia, and nuclear weapons are not even a credible deterent in this case. As long as we can guarantee total and complete air superiority to the north of Australia (which we have had for 30 years and will probably have for another 30 years at least) there is no way that the Australian mainland could be invaded by any feasible enemy.
