Whatever Happened to Superman in Australian Supergirl comics?

If I ask you to name a Superman story involving a breach of the Fortress of Solitude, Supergirl in a support role, and illustrated by Curt Swan, I'm betting the first story you'll think of is Alan Moore's Whatever Happened to the Man of Tomorrow? in Superman #423 and Action Comics #583. And rightly so - it's a drop dead classic.

However, if you're steeped in Superman lore from the 1970's, you might upon reflection consider a lesser-known story which appeared in Action Comics #411:

This is the issue in which Superman is legally deemed to be a squatter! In a nutshell, an oil prospector has purchased the land on which the Fortress of Solitude stands, and as such the building and its contents legally belong to one T.J. Person, and Superman's lawyer advises him he has no rights in the matter. Of course, Superman finds a way out of this mess - no spoilers here - but you gotta love the mock-earnest 1970's riff on silver age goofiness in this synopsis.

I'm still a big fan of this era of Superman comics, especially anything with Swanderson art. Yet remarkably, I only came across this story recently in, of all things, the Federal Comics edition of Supergirl #1:

This issue was published in 1983. However, it turns out that The Day They Sold Superman's Fortress was published some 10 years earlier in Supergirl Comic #5:

 

I know for a fact that K.G. Murray Supergirl issues are a prime focus for at least a couple of KGManiacs, but I'm not one of them, and never have been, so I wouldn't have read this issue as a kid, hence my coming late to a story I would have thoroughly appreciated as a 10-year-old when I was buying Planet Comics off the shelf. By the time Federal Comics were in town I'd well and truly stopped reading comics. But, if I had been reading them over that 10-year span, I would have preferred the Supergirl Comic #5 version over the Supergirl #1 edition, purely for the botched layout of the title splash page. Compare the following:

Supergirl Comic #5 pp 14-15

Supergirl #1 p. 9

Supergirl #1 p. 10

It's not just the flow from the one panel to the other which works in the two-page spread, but the text box caption leads into the title. Splitting the two pages - and having to turn the page from page 9 to page 10 - extends the timing, and suspends the resolution in the caption box.

There was even more editorial tampering in these two editions. Here's a scan of the first page from the original presentation in Action Comics #411:

The reprint in Supergirl Comic #5 replaces the classic "Superman" masthead with what appears to be a homegrown facsimile:

The subsequent reprint in Supergirl #1 takes this a step further by adding the "Supergirl" masthead, contriving a fully-fledged team-up story: 

Not what one might call a Federal crime (sic), but hey - if we didn't obsess over this minutiae, we wouldn't be here.