Ethan,
You probably already noticed the other thread on this subject, but just in case you did not... (added: Duh, I just saw your Sept 1 comment in the previous post - well I guess I failed that reading course again

)
Please note that as of Sept 1 the savings will not be quite so good. Fares for a AONE4 in Srilanka will be going up on Sept 1 to aprroximately 5020£/11822 AUD. See
this link for more info.
For an AONE4, that compares to 6949 £/16364 AUD ex-UK or 5749 £/13539 AUD ex-OZ. Still a good savings, although not nearly as substantial in Australia. As you say NZ, at 5417 £/12755 AUD, comes close and may be more convenient.