You could try here . . .
Classifieds
. . . and just note in the sale title (Australia).
Can probably only ground ship
batteries.
I have extensive kit for mine, but for the past 6 months just haven't had time to fly almost at all, just checking
batteries every few months on the Spark and M1P kits.
So I know your pain.
Did you update to a newer model / other brand drone ?
For me it is more that I used the Spark for travel, which is still limited due to the travel / border fiasco here, or I'm just too darn busy with the 'W word', too busy to do much and now in the habit of not flying once or twice a week.
Other alternatives, maybe Gumtree, it's free and works ok with an occasional 'tyre kicker', who you can get rid of pretty quickly.
Facebook Marketplace is supposed to be the #1 place to sell now, but alas I don't do social media apart from the drone forums and YouTube.
I would certainly list it here in the classifieds, maybe even put a 'farewell' post in the Australia section linking that.
(You might not actually be leaving here full time, but it will help hits form Aussies that might see it there
)
All the best with it.