Hi Rosemary
You certainly have a mystery on your hands, here.

The letter from Trentham is intriguing ... and yes, seems possible Hillyard had "another first name" ... (you'd sort of like to think that it began with the letter "G" ) ??

I'll get back to you on exactly what army resources are available.
In the meantime, can you just clarify the following please?
In your other thread "Immigrants - Blue Registration Form - 10 July 2007", you confirm that "Gordon Campbell STUART born 1922 and Aileen Dorothy STUART born 1924, are part of this family". I'm presuming that means they are also children of Hillyard and Dorothy ?
That being the case, do you know where
these children were born ?
Just one more favor .. could someone just check if there is a birth of a Douglas McNiven in NZ 1920 ish. ?
Not sure whether this question was ever answered ?
Can confirm that there were NO New Zealand registered "McNIVEN" births in the years 1918 to 1920 ... (and in 1921 only a birth for a female "McNIVEN").
I find it a bit curious that Hillyard has stated that he retired from the Australian Navy on 20th February 1920 (of course we don't know from that whether he was physically 'in Australia") ... and just a matter of weeks later, his child is supposedly born in Auckland (6 March 1920). And what of Dorothy ? Has she been living in NZ whilst he was in the Navy ? He was also c. 44 years of age when discharged from the NZ Army - seems a little strange perhaps that he'd link up for service with Navy ... and in Australia ?
Could Hillyard's year of birth be wrong ??
Do you have his death certificate ??
Lu