Possibly not, but if they can integrate the flight with domestic flights from the east coast then they could offer a one-stop journey from the east coast to LHR. That might make it a more viable proposition, especially if they can provide an easy transfer in Perth.
Makes no sense to me that. What's the difference between flying from Sydney to Perth and then onto Heathrow to Sydney to Dubai/Singapore/any far east country and then onto Heathrow?