It seems that slowly the UCS Millennium Falcon is becoming less impossible to buy. The latest option is to pre-order the set from Toys R Us. They are charging RRP but you will also need to add in postage.
The catch that may make this less appealing is that the item is due for delivery in March. If you are happy to wait then it is an option worth considering. You’ll also get Toys R Us VIP points worth about $10.
You can pre-order the set via https://www.toysrus.com.au/lego-star-wars-milennium-falcon-75192_8013781/
Thanks to David for letting me know about this.