Thank you Amondg. I'll look into the death of the Susannah Wright who died in Surrey in 1939. Yes, that's definitely worth a look. I didn't know about that.
I knew about the connection to the Duke family i.e. Susannah's sister Sarah and her husband Edward Duke. I knew that Susannah and the children lived with them in Thames Ditton for a while. Thank you for looking into it and confirming this.
I didn't mention a name before, but Mabel's wild guess is correct. I knew that a few years after Susannah's last child Roland was born, O. J. H. did eventually marry (in the late 1880s) a woman called Emilie with a similar social background to himself and they had one child (a daughter born in 1890). However, he died in Johannesburg, whilst on some sort of business trip in 1900. I only found out when and where he died very recently myself. I researched his family in Germany i.e. his parents Carl August Herrlich and Bertha Weber, a while ago. I would like to find out what happened to Susannah, but I'm hoping that it is good outcome, rather than being cast out into poverty or struggle for years.
Many Thanks,
Sarah.