That helps so much - thanks!
A public Family Tree on Ancestry.com has
Ebba's father** as
Martin Frederiksen born 30 JAN 1886, Den Kongelige Fødestiftelse in København. Occupation Brolægningsarbejder
Ebba's mother is listed as
Inger Amalie Møller**
born 22 NOVEMBER 1885 in Køge [= Køge, Ramsø, Roskilde, Denmark]
died 23 JULY 1931 in Elias Sogn in København.
Inger Amalie Møller first married
Niels Oluf Nielsen 15 Oct 1905 "Kristikirke" in Copenhagen.
She next married Martin Fredricksen 21 December 19XX (13?) at Elias kirke in København.
The tree shows a daughter for Inger Amalie Møller and Niels Oluf Nielsen, Erna Laura Nielsen born 04 NOV 1907 in København. On 17 December 1926 Erna married Holger Magnus Holm b. 1904.
**Note: Inger Amalie Møller and Martin Fredriksen are said to be parents of two children. Both children are marked "private" and no information whatsoever is visible about them. However, one of the children is married to "your" Svend Aage Andersen.
Here you have another online family tree showing this family:http://johnoglis.dk/genealogi/getperson.php?personID=I75748&...
Both trees show Inger Amalie Møller's father as Ludvig Jeppe Møller born 1843 in Hesselbjerg in Rerslev Sogn, Løve, Holbæk and died 1925 in Køge. Inger's mother is Inger Hansdatter born 1847 in Højelse, Ramsø, Roskilde and died 1909 in Køge. Ludvig and Inger are shown with 8 children. Inger Amalie is the youngest.
Of course online trees need to be verified. The trees don't help with the immediate question but perhaps can lead to a connection.
Here you see an online discussion of the family of Ludvig Jeppe Møller (supposedly great-grandfather of "your" Inger Andersen who went to Australia with Helmuth Hansen).http://www.slaegtogdata.dk/forum/index.php?topic=17664.0;wap...