Excellent advice to use CX, they can certainly do this and don't have the exorbinant fees of QF (and BA). AA can also do it at their office in North Sydney (but I guess that isn't north enough for you). Obviously you have to do this in person, as you must surrender the paper ticket before the e-ticket can be created (which limits your choice to the airlines with offices at CNS, I suppose). I suppose the problem on an L fare is you don't want to be on CX for most mileage plans, and the CNS office is probably thinly staffed and not keen to be doing this kind of exotic work. Technically any OW airline can reissue OWE tickets, you don't have to be flying on them, but in practice they won't unless you are flying one of the 3 inter-zone legs on them. I guess you flew LA and about to fly AY for 2 of those legs, the trans-atlantic was obviously not on CX, putting you in a very poor position to ask for favours (as your ticket revenue is going to LA and AY, not QF or CX).