Looks like a very unique piece! Wonder if it was imported...

I would say that is a custom-built timber post and a standard galvanised metal letter box. You could DIY or see if a local carpenter or even handyman could make one for you. Timber post, post capital, decorative verandah bracket, basic piece of timber for the letter box to rest on/attach to.

Happy Easter to you as well, I would try your local second hand building material yard, old doors etc, they quite often have bits and pieces. Elraco is an online store in Sth Australia, excellent to deal with https://elraco.com.au/index.php/escutcheons-c-28_1288_1294?page=2&sort=2a

Hi there! Does anyone happen to know what this light is and where I could buy it - or something similar? It is to go in a hallway and mounted from a ceiling Rose - so the base can’t be too wide. Would appreciate any help. Thanks so much!