Help finding flights to Australia please

jnm21

A friend knows that I have a good record in finding cheap flights, so has asked for help, however I am a UK flights expert (living in NI with a regular need to visit the in/out-laws in GB several times a year).

Basically the requirement is for him to be in Melbourne on/before Christmas day & return from Sydney after the 10th January - he is not worried about an internal flight between the two at this stage, but if one on new year's eve happened to be going cheap........

Cheapest I can find is around £1300 from Belfast to one or the other, but I can't find anywhere reasonable for a Belfast-Melbourne + Sydney-Belfast ticket. Any suggestions? Also any airlines to avoid, e.g. China Eastern, or are they all safe nowadays?

Thanks