CGT is worked out using the date you purchased the Options, and...

CGT is worked out using the date you purchased the Options, and then the date that they are sold. If you hold them for over 12 months, you're eligible for the 50% CGT discount.

However, if you convert the options to shares, capital gains would be based on any gains/or losses starting with the date you acquired the Shares (not the options), and then the date you sold the shares. (discount if held over 12 months). The cost basis for the purchased shares would take into consideration the cost of acquiring the options and the 1.5c exercise price, plus brokerage.

NB. This is not financial advice!