I'm with Mac on this one. Then good, firm, prescriptive wording is the key to avoiding many (not all) of the f-wits who want something shipped to Tierra del Fuego for half your asking price.

Good luck!
Edit: Soz if this is patently obvious, but if you go to gumtree, longboards, surfing and set it to all of australia and then set your price bracket (say 900 to 1400) you get a pretty good snapshot of what is out there and where your board sits in comparison. Cheers.