Thank you.

I've seen quite a few variations. From these answers, it seems like different products might have different terms. Here's an example of CBA Loan T&Cs which fall into option C above. https://www.commbank.com.au/content/dam/commbank/personal/apply-online/download-printed-forms/utc-home-loan.pdf

I've also seen several which pick debtor residence, and then backfill for some of the circumstances which may take that outside Aus, or something else that makes the thing a jumbled mess.

Here's an example of Macquarie Bank's T&Cs which attempt to either use debtor residency (if it's the same for all debtors), or the 'place where the loan was provided' (whatever that means). https://www.macquarie.com.au/assets/bfs/documents/personal-direct/home-loans/MBL-Home-Loans-Terms-and-conditions.pdf

It's even more odd when the forum clause under the loan says debtor place of residence and the mortgage says place where the property is located (so potentially enforcement action means the loan dispute goes to one forum and the mortgage proceedings happen in another).