The intention is for the LHR-HKG-SYD eventually to become an A380 schedule. It will start on the A346. While it's possible that a second LHR-HKG is on the cards, it's not being proposed at the moment as far as I am aware.
This route has been planned for some considerable time, and the airframe and personnel planning have anticipated its introduction - it is the primary driver of Virgin's current recruiting programme and the recently-increased A346 order. However, there are more new routes on the cards and Virgin has gone on record recently to say that it intends to be twice its current size within 10 years, via a planned growth of approximately 10% per annum.