Thanks ZKNHB.
Maybe I should have used the term positioning rather than deadheading.
Assuming the 787 cabin crew stay overnight they would then return to AKL together with the 777 crew who operated AKLPER the night before on the usual 777 flight. So both crew would be heading back to AKL on the one 777 flight.
Otherwise the 787 cabin crew would be in PER for the next 787 flight 3 or 4 days later. Just curious how this works!