If anyone can add to the story that I've pieced together as per below - please do!!
Elizabeth Low married Alexander Alexander in Dundee Scotland in 1829.
They had Alexander, Agnes, Betsy & 2 males who predeceased their mother.
She then married Laurence Donald in 1847 in St Andrews Scotland and had Wilhelmina & John.
Wilhelmina married John McKinnon in Shotts Scotland in 1872 & had a son John.
Elizabeth seperated from Laurence & headed to Australia c1874 - probably with Wilhelmina & William as their next child Alexander was born in 1875 in Sydney Aust.
Elizabeth's son Alexander & his family came to Aust in 1876 & it is possible that the other 2 daughters & ?families came as well.
Elizabeth died in 1888 - aged 81yrs.
Wilhelmina remarried in 1890 to Rees John and had 2 sons.
In 1920s, the close family were made up of Mckinnon, Creswick, McLaughlin & John and many of the children have the middle name of Low, Donald & Alexander.