Hello Tazzie
Thank you so much for your reply, it was great to see it this morning. Using the information you provided, combined with mine, I have been able to work out that Caroline Isabella Cogan & her husband are my great grandparents and Caroline & Robert Thomas Cogan are my great great grandparents.
Frederick married Madeline Alice Wilson on 17 April 1907 and on the marriage certificate his father's christian name is listed as John. This is confusing because I have a handwritten list of names, dates etc. that Frederick's daughter Betty, my aunt, wrote out for me and I have assumed his name was Ingram - maybe John Ingram. She copied it word for word from the front pages of his Bible which is now in the possession of one of my two cousins. I also cannot quite figure out how many siblings Frederick had.
Frederick passed away May 29, 1969 and Madeline April 9, 1932. I'm not sure if you know but Frederick and Madeline are buried in the same grave, next to their daughters Alice (my Mum) and Betty at Macquarie Park Cemetry, North Ryde in Sydney. Caroline Isabella, who I had been told was quite formidable, is buried about 4 or 5 rows away. My husband and myself visit quite regularly with flowers and do some maintenance but due to covid restrictions haven't been since May.
I had seen a reference to Euroka Street in one of the posts - that is where Frederick moved to after Madeline died and it is the house that I grew up in. He worked on the Sydney Ferries for many years and unfortunately had an accident that led to retiring early because he lost a leg - I don't know the full story. Grandfather never spoke of his siblings in my presence but I do know that there were relatives in Sydney at one time.
I have a photo of Frederick on his wedding day, it's a copy of the original which I store separately because it's fairly fragile now. I also have a photo of Madeline, which is the only one I have ever seen of her but it is the original.
If you want to write again, it would be lovely to hear from you.
Best wishes and stay safe
Bronwyn