Mary Elizabeth GRAHAM, born Maryport c1883

[Voltaire1694]

A John Wallace MCGOVERN died on 5 October 1966 (aged 57), in Woodville Gardens in South Australia (https://www.genealogysa.org.au/resources/online-database-search). So definitely the one!

Which explains why no children were mentioned on her death notice in 1980, perhaps no grandchildren (tbd).

[maddys52]

For interest, there are quite a few mentions on trove about the Berrima voyage in 1927/28 which brought  a number of "boy migrants" to South Australia. It was also delayed due to bad weather, and the 2nd engineer died on the voyage.
https://trove.nla.gov.au

[Voltaire1694]

... Possibly the Mrs Mary Elizabeth McGovern who set sail for Australia on 8 Dec 1927, with a son.
... Modified to add:
They sailed on the Berrima. Her address 162 Chatham St, Abercromby, Liverpool. (image on Ancestry)

Super helpful! Thank you. The Berrima arrived in Adelaide on 25 January 1928, with Mrs Mary E MCGOVERN (aged 44) and John Wallace (aged 18) (https://www.archives.sa.gov.au/__data/assets/pdf_file/0005/839156/GRG_41_34_0_555-1928_Berrima.pdf).

[Voltaire1694]

I just wanted to thank you all for your help above. Very much appreciated.