A UK Will can be used by executors if the deceased has assets in Australia, but would most probably require resealing if it is to be capable of being used.
It is likely to be quicker for the executors if there is an Australian Will to administer Australian assets, and a UK Will to administer UK assets.
Also for consideration:
> Power of Attorney in SA
> A Domicile Statement, if the net estate will trigger an Inheritance Tax liability in the UK.
> CGT in Australia on death if any CGT Assets in the estate are bequeathed to a non-Aus resident beneficiary
Feel able to contact me via a Private Message or email if you would like to explore these issues more fully.
Best regards.