Thank you Gardyloo. I do have a subscription on EF. Indeed, JL52 shows lots of D seats available in late February, however, the online tool doesn't show the lfight as an option at all.

So, you agree that JNB-x/HKG-MEL is a valid connection even when entering Asia again flying SYD-HND? Because i guess i have to convince the agent that all is withing the rules for a DONE5