A bit of digging turns up some interesting info. There were 2 titles;
The Invisible Avenger, #1 - 11, 1950 - 1951
and Invisible Avenger Comics, #11 - 28, 1951 - 1952
This one mainly featured The Blue Ghost.
The overwriting may have something to do with a further complication. These titles, or some of them, had New Zealand editions. Changes might have been made for the NZ issues as can be seen on the back page of #17.
Illustrated Publications published the Aus. comics.
By the end of the run the contents were mainly American reprints; Atlas, St. John etc.
Link to the book:
Invisible Avenger 11