That would be why then. If you have a copper cable then getting FTTC is pretty much plug and play. If not then you need one put in. Generally NBNCo will install it for you but putting in conduit from the street is what they consider a complex job.
You could put in your own conduit (get it done) from front of the property back to where you want the inside wall port to be. Place a draw string inside. Then contact a RSP and say you are ready to be connected now. They may be able to prob NBNCo to come out and reassess and do the install.