tax on capital gains, page-57

just wondering if anyone uses the LIFO method for CGT and profit/loss

I have never let my holdings of ABC company go below 50,000 shares since the 1st of July 2017.
In addition to those shares in the same account I have bought and sold about 1 million shares for a profit that gets me into the 1st tax bracket.

Using FIFO I have a gain of 150% on the LT 50k shares for FY 2017/2018
Using LIFO I have an unrealized gain of LT 150% on the 50k shares for FY 2017/2018

This article states that you have to advise your Broker which method you use. I contacted Broker ANZ and they are unable to take a request of this nature. To me, that means it defaults to what I and my accountant nominate .
https://www.fool.com/knowledge-center/how-to-sell-stock-with-fifo-or-lifo.aspx

My accountant only uses FIFO, all I have to do is convince him that LIFO is a legitimate trading strategy.

Thanks