Hello from Brisbane.
I genuinely admire your commitment to your project, but maybe would be personally inclined to consider looking for a less rusty donor vehicle for those rotten body parts - it may be more economical in the long run.
I have a friend in South Africa who recently bought a Series 3 wagon with an aim to restoring it. Problem was that while South Africa is generally a dry place, and extensive body rust isn't usually a huge issue, his vehicle came from Port Elizabeth where it was used for pulling boats out of the surf. He also thought they were all aluminium..... Anyway, over a few conversational Castles he resolved to head west into the Karoo to try to find a suitably cheap donor with a good body and stuffed mechanicals.
Returning to Oz for the moment - I occasionally come across lost Land Rovers and some of these would possibly be useful for the type of restoration that you are working on. As just one example, these two trucks are languishing in a machinery yard near Dalby:
From my observation neither had a lot of rust and would fit a wagon like yours - as noted in an earlier post (JDNSW) the doors, frames etc were interchangeable from S2 through to Defenders.
Not necessarily suggesting you seek out these particular trucks - rather that it might be easier and quicker to make progress with a suitable donor.
Cheers,
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