Melburne or Melbourne?! ;)
Anyway, having done 5 container trips now around the world - a 20ft container has an inside volume of 31m3 - ie about 2.5m*2.5m*5m (w*h*l). A 40ft container is twice as long (10m).
You can ask your removal company to have an exclusive container or you can ask to share. Sharing will be slightly cheaper, but then you are waiting to find someone else to fill that spot.
Also you have no control on what goes into that container when it is shared. It also makes customs a nightmare because you & the other party have to co-ordinate being both there for the opening of said container at customs.
Make sure you are fully insured. I had a friend who was insured, but also shared a container. The other half of the container was filled with re-inforcement bars for concrete that werent tied down properly. That combined with a rough sea pbuttage meant her stuff arrived in pieces the size of talcuum powder :( Another friend moved to New Orleans recently. As you may have noticed there have been a few problems with wind in that part of the world. His container never arrived and never will arrive.
Send your really really valuable-sentimental stuff air-freight or in your luggage.
--