Hi Debra ... Re marriage Bertha Annie Welsh marriage to Walter Arnold Johnston 1886, I certainly didn't think of that angle that Bertha being underage, she would have needed her mother or father permission to marry as we know her father had passed away so it looks like her mother too and therefore JP needed to give authority for her to marry. I will certainly contact the Presbyterian church to see if they have the church records for the marriage of her parents, thanks for that, also JM for the link.
With regards to Bertha's father William Welsh and his first marriage to Christina McIntosh, I found a record on the LDS site; They married 11 Apr 1849 at Wicklow Ireland. They arrived into Sydney on the 'Victoria' 04 Sep 1849 as full paying passengers (interesting to read his comments about the voyage!) William stated his father, 'William Welsh' was residing in Sydney at 'Brickhill' however I haven't been able to find anything on him as yet and this is another thing to track down
I've only been able to find 2 (not 3) children, Eleanor born 1850 NSWbdm # 1221.35, surname spelt WELCH. George (but no luck finding a NSW birth reg.,) but a death notice SMH 13 Sep 1859 page 9 lists the death of George Welsh at 9 Little Gipps St. Surry Hill, aged 15 months, parents William and Christina.
Re death of Bertha Annie Johnston nee Welsh. The informant was my husband's grandfather, Robert Johnston, so as you say, it seems that he and his many siblings had no knowledge of their grandparents.
What I can't figure out what was Bertha doing in Melbourne? Her husband Walter Arnold Johnston was born there and I don't know if he came to Sydney and they ran away together, back to Melbourne
and what happened to Bertha's mother
I am still sorting out information received yesterday re Elizabeth Welsh nee McLellan's birth and parentage and will do another post soon with what I too have dug up.
Thanks again for your great suggestions and anything else you may think of, I would very much appreciate your input. Bonnie