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Isn't Dragons Rest in Australia? Have a look at their Dragonfly and Grasshopper ships.https://tabletopterrain.shop/products/sci-fi-grasshopper-dropship
How about this? https://miniaturescenery.com/index.php?main_page=product_info&cPath=12&products_id=114 It's not cheap, but is an Aus-based company.Also, see this thread http://leadadventureforum.com/index.php?topic=124162.msg1566043#msg1566043 for toy suggestions that might work. (I've got myself a pair of the Avengers Quinjets off the back of it.)
Papercraft is indeed a very economical option that yields good results if you are willing to put in some effort. Of course only of use to you as soon as you can buy a printer but there is a papercraft version of this dropship around that can be found here:
I picked up a Shuttle Alpha from a 3d print company for fifty pounds. Only five pounds more than a GW Valkyrie. I am sure that someone on your hemisphere is either printing them for sale or would print one from STL files. It can be printed in both 15mm and 28mm. If there is not a online printer that carries them you can order the STL and have them printed with a local printer. https://www.myminifactory.com/object/3d-print-space-shuttle-alpha-75556They scale well for 28mm and are modular.