> I presume other Commonwealth countries) default to paracetamol (acetaminophen) before ibuprofen

Can confirm this is true in India.

Paracetamol is widely used. Paracetamol + Ibuprofen is more common than Ibuprofen by itself.

> Australians (and I presume other Commonwealth countries) default to paracetamol

The same is the case in the Netherlands.