I lived in Dampier for 16 years, now that was 14 years ago. I bought my grain by the sack and had the local coke delivery guy pick it up and drop it to my door, back then for the price of a carton of mega swill. I think I still have him number somewhere but chances are he's moved on. There was also a guy that had a home business in Karratha that did home brew grains etc. A quick google looks like he's still there
Pilbara Homebrew Supplies