Who says that LHR crew will just operate to DXB ? They could easily cross crew and send crew through to SYD or MEL as 7-8 day trips.
There are planned ground schools for secondments for MAM to QCCA A380, QD/QAL to A380 and also AKL based Jetconnect crew will be converted to A380 from November( not sure if it will be a sole A380 endorsment or additional endorsment on top of their current 767/330/744 ).
With the massive increase in crew numbers for A380 fleet I suspect all crew regardless of base will follow QF1/2/9/10 to the final destination in future patterns.