I'm looking at buying a watch online, value over $1000 but I'm baffled by the duties, fees, taxes on taxes that I also likely have to pay and the forms I have to fill in to avoid some of the fee, but which incur another fee to process. So I'm wondering if anyone has done similar recently who might be able to point me in the right direction or clear up some of my confusion? Is it worth using an importer to do the fees and forms for me?

My understanding so far is I pay 10% GST, and from that new total I then pay 5% import duty on top of that, then I fill in an import declaration form and pay a fee to lodge that. Failing to lodge that form could incur higher fees when border force receives the parcel and they process it?