It may be a decade or more before Australia actually gets any nuclear boats. The CCP will continue to move incrementally but 10 years for them will be a lifetime to finish off Taiwan along with their key needs in the South China Sea. And unfortunately I don’t see India going anywhere in that time.
China would wither in a minute if all countries stopped buying from them but no one wants to decouple from China. Too much money to be made.
Here is one possible scenario. Refurbish one of ours and sell it to them. Probably about two years for this. Have them train for a couple of years on the boat. Meanwhile, we build a new boat partially paying for it with the money from selling the refurbished boat. Do that a couple of times and they have several crews trained on nukes and we get a couple of newer boats.