Thank you all so much for your help!!
I did know about the loss of my grandfather's oldest brother, he is referred to as Jack on his parents' headstone. Donald Victor had a terrible time in France, his record suggests that he had very bad shell shock. His son, Glen was 18 and an able seaman on HMAS Sydney, and was lost in1941. That poor man!!
It would seem likely that Christina Campbell MacIntyre was Malcolm's mother, I'll send for a transcription of his death cert to check, thanks for the link,Cando. Priscilla's mother was Margaret Ford, so they named their only daughter Christina Margaret.
I have been in touch with Centennial Park cemetery, about the licence on the grave. The licence is in Malcolm's name, as Priscilla predeceased him. The law says that the licence can then pass to the next oldest relative in the direct line. So, Jack died in WW1, the other brothers and their sister are no longer here. My grandfather was the youngest, and I don't know if there is anyone else "higher up" in the family line to pay the fee and take over the licence. I have a form to fill in to do this, but thought I'd kill 2 birds with 1 stone, and see if there was anyone here at Rootschat who may be related, PLUS someone might be able to assist with my query about Malcolm's family. Mission accomplished, I think. I have some very good lines to follow, and I think I'm going to fill in the form for the cemetery, and take over the licence myself. I can't bear the thought of them reusing the sight. They are MY great grandparents!
Thanks again Jenn, Floozy, Cando and Sue. Much appreciated.
Jude