Anyone come across this before:

We have registered a business name (lets say 'ABC') because we want the
domain name for this business to operate under: www.abc.com.au

There was a previous business called 'ABC' but it has ceased trading. Shows
this in the ASIC database. However they earlier registered www.abc.com.au
which is still registered by them but there is no 'live' web site present.

QUESTION:
Can they still 'own' that name when infact their business is no longer
registered/operating?
What steps do you have to take to have some authority 'release' the name
from this deregistered business?
How can we find the expiry date for this domain (legally)?
The registrar is Melbourne IT

Chas