We have a unit in Southbank and we let it on airbnb. As we live in Queensland, getting keys to our guests has presented problems. This has been solved as we are now able to leave keys with Dan and Ash who run a cafe on Miles St. We let them know the name and arrival time of our guests and Dan or Ash give them keys. When guests come to the end of their stay they return a set of keys to the cafe. Dan and Ash also offer other services. If guests arrive before the accommodation is ready they can leave luggage at the cafe. Conversely, if they have a late departure but have been required to leave early then luggage can be left. In addition to this Dan and Ash will accept parcels and mail for guests and hosts should such a service be required. In fact, I think you could ask them to help with almost anything. There is a small fee for the various services but so worth it for the peace of mind.
If you would like to inquire about any of this contact them on their email *sensitive information hidden*
Marian