Hi,
You need to be really methodical here a get all the information you can.
If you are happy this is your great grandmothers birth certificate.
The next step is her parents marriage certificate.
Their date of marriage is in 1857 as given on the certificate, so should be relatively easy to find.
This gives their parents.
Now look for all their siblings, this makes them easier to find with certainty in the census.
Get all the census returns, you may be lucky and find one with a relative visiting or similar.
This should give approximate death dates for their parents.
Repeat this process with the parents, this will be pre certification, so you won’t get their parents from this, but looking at the dates, you may well be lucky and the grandparents die after 1855, giving certificates which will give their parents names.
Scotlands People have been upgrading their index recently, making it a bit easier to find people. They say that mother’s maiden names are not always in the index pre 1974. But there are a lot more now, and the other name is more often in the index as well.
There is a possible Robert McGregor dying in Rothesay in 1912 mmn Porteous
And a possible Helen McGregor mmn Adams in Perth in 1895
There is also a possible Robert McGregor in Perth mmn Campbell.
But as others have said, do your own research and read the original records, there is lots of information there not in the index.
I haven’t reviewed this in the light of your later posts, but the principle remains the same.
Happy hunting
