I did some googling to see if there was any trace of my great-grandmother in Tonga - having been there I wanted to see if I could find out any more. I couldn't; although it's not really surprising as she would have been a child or teenager - and a female one - hardly the stuff of historical record. However I did manage to find her father, my great-great-grandfather, in a number of newspaper reports back from Tonga. His name was Arthur Wright and in 1897 he was in Vava'u - according to an article in the Launceston Examiner of 8 April - where he "kindly welcomed" the writer and "exhibited the process of manufacture of copra".
The other mention is in the Sydney Morning Herald of 20 November 1902 - apparently they had a correspondent in Nuku'alofa who wrote an occasional "Letter from Tonga". I don't know how legible it is, but here's the relevant extract:
So it turns out my great-great-grandfather was the chief mover in founding the International Temperance Society of Tonga. I did find a photo of me in Nuku'alofa on my birthday - very happy, but perhaps not doing the family proud.