Hi Prue and Michael
I am also the 3 x GGrandaughter of Margaret and Edward. Williamina my 2 x GGrandmother married Charles Goodwin (also hard to find anything about. Their daughter Elizabeth who married William Threadgold is my Great Grandmother. Her daughter Linda Threadgold who married Colin Gill is my Grandmother and her daughter Tasma Gill who married Brian Martin is my mother.
How are you related. I guess if you have read the book that it doesn't shed any light of Margaret's family. I have been researching her (without success for 15 years!!) I am happy to share any information with you.
Jane Stillwell (nee Martin)