Dear CD,
The law that governs BFAs is the Family Law Act 1975 (or the Family Court Act 1997 if you are in a de facto in WA). This legislation does not cover testamentary intentions, and if included in a BFA, those intentions will not be enforceable.
A BFA is designed to document how the parties to the agreement intend to financially settle in the event of separation. If either party passes away during the life of the BFA (i.e. the parties have not separated before one party passes away) then their estate is distributed according to their will, or if there was no valid will, the estate will be distributed according to the intestacy laws in the state or territory in which the deceased lived, or otherwise, in the state or territory in which the particular asset is located.
Please look up the “Succession Act” in your state or territory for specifics.
In your situation, to protect the financial interest of your partner, you should write a [new] will that makes provision for them in respect of the particular property that is in your name, but to which she is entitled to 50% of the net equity.
If you do not, and you pass away, the property will go to the beneficiaries named in your will, and there is no guarantee that they will honour your informal wishes and provide the equitable share to your partner.
With respect to your will, you can write a will to the satisfaction of your partner, but that will can be changed at any time without the consent of your partner or their knowledge. In the worst cases, the will was changed by the family members when the testator was suffering from dementia!
I suggest you consider a binding will contract.
This is when both parties prepare new wills, and also sign a contract that binds the parties to those wills such that they may not change their will without the consent of the other party to the contract.
This means that the interests of the party are protected, even if a manipulative family member tries to have the will re-written.
The BFA and the binding will contract should be done simultaneously to make sure they achieve what you and your partner both intend the documents to achieve. And it is much cheaper that trying to litigate after the death of the party.

Kind regards