The problems could be simply that the channel bandwidth used in the UK is 8MHz (PAL I standard) where as Australia uses 7MHz bandwidth channels (PAL B standard).
So simply the tuner in your TV receiver is looking at the wrong frequencies and expecting an 8MHz bandwidth for a DVB-T signal.
FYI I have a DVB-T receiver that at day 1 "start up" you have to select your country. If I choose Germany then it searches in both the VHF & UHF bands - which you would expect and finds UK DVB-T (in UHF)
If I select UK and scan it looks only in the UHF band.
If however I switch the country to Australia and scan it finds nothing!
I sugest you need to check the Software\firmwear version in a similar TV sold in Oz.
I hope my post has been of use