"Clearing out" does not constitute "exporting" the vessel.
Since it has only been out of Australia
for eighteen months it should not require re-importing. Not sure of what the period is but believer it is considerably in excess of the eighteen months.
Don't know if the rules have changed but it used to be that duty payable on vessels taken overseas for refits was only payable on the cost expended on the refit
and not the entire vessel.
A factor which might impact upon how the transaction is treated is whether or not ownership
of the vessel changed which it was overseas. You are supposed to have the registration
amended within 14 days of the sale
from "revenuers" is always suspect, a broker
who deals in overseas sale
of vessels might be a better place to go.