Many years ago I did just that for my now late father. He was old and could not remember anything except roughly what year he bought the shares (Westpac). I called the ATO and the nice gal there said just go to that year, take the highest and lowest price and use the middle as the cost base. I don't know how it works now but you can always call them and workout a solution.
APA Price at posting:
$11.44 Sentiment: Buy Disclosure: Held
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