I received this targeted offer via email. If you've been targeted then you would also see the offer on the main page when you login to your My Dan Murphy's account.
The interesting thing I found was that if I order again, then an unexpected thing happened. :-) If you've also been targeted, then you might want to try ordering the same thing again, to see if you have also been lucky.
They claim that it applies to "all liquor" products, but I found that a few liquor products (like the Koyomi Highball) are excepted.
Is there a code or does it just apply at checkout