Wallpaper is a rarity in Australia. Very few people use it, hence almost no shops sell it. I remember noticing the lack of wallpaper shops when I arrived here.
And as for finding anyone to hang it for you ? I wonder if the Yellow pages even has a section for that.
When you can find wallpaper locally in Australia the price may be a lot higher than the price in the UK including delivery to you in Australia. So I suggest you check out that option before committing to a purchase, but also consider the difficulty in returns…
Wallpaper suppliers in the UK that deliver to Australia