Doesn't seem to appear - @Warin61, the other thought I had was to make a smaller landuse=residential here with the complex name, but wasn't sure of the appropriateness of having nested residential areas. Any thoughts on that?

Fixed thanks

Thanks for pointing that out, I wasn't aware. I originally was considering site relation, however was dismayed by "Site relations have poor support among data consumers, so consider better supported alternatives for what you are trying to map."

Looks like it is the best option nonetheless, and i'll change it over

Cheers mate, appreciate the guidance and care here -- I've just recently moved from Seattle a couple years ago, so I haven't looked into which community channels were active in Aus (except for slack) - I'll join the mailing list, thanks for the recommendation

Hey thanks for the detailed explanation -- I think what you mentioned is likely true, the suburb admin boundary should contain the postcode.. i haven't seen that done, but i'm sure somewhere has an example. After my message I also started exploring nominatim and discovered what you described, that the post code is inferred from the surrounding addresses (which relies on at least some addresses having them :) ). I think I'm somewhat on the fence about whether there is any harm in completing the address
per way/node, though you've shown that in at least many/most cases its not necessary, and it appears as though nominatim itself is the key to finding these boundaries with OSM -- On the other hand, I'm respectfully not convinced that it is harmful to include these tags (as far as bloat goes). I am on the fence about removing or keeping the challenge active. Most of Australian addresse node/ways provides addr:postcode along with a suburb+street. I think Australian Tagging Guidelines could benefit with some clarity on addresses in general, but not sure of the correct forum to start that discussion. At least discussing the merits of the default keys provided by id in Australia

Hey, thanks for asking.. if you have insight into how mapping software uses this data (i'm making a lot of assumptions), I'd be interested. But my assumption is in general that the more complete the data, the easier the load is for mapping software to get it right without relying on looking up the chain. I don't actually know where postcodes are registered on the large-area level. I've looked at suburb level administrative boundaries, and they do not seem to have it tagged, yet OSM search is able to offer the postcode