Great to get some replies so quickly! I have the 1841 Scotland Census entry for David BARCLAY & family, including a Georgina. The entry has some possible transcription errors as Janet BARCLAY's age is stated as 20 & her 2 daughters 10 & 9 which would mean she had them when she was about 10! Or the other possibility is that David & Janet are siblings of Georgina & Elisabeth, not parents?
I can't find them in the 1851 Census.
I also have the Elisabeth BARCLAY m John MITCHELL info. Their marriage record has her parents as Andrew BARCLAY & Jean RITCHIE. But I can't find a dau. Georgina connected to Andrew & Jean BARCLAY. There appear to be 3 farms involving SMITHs (Balmeadie/ow Farm, Dunbog), BARCLAYs (Johnstone Farm, Dunbog) & MITCHELLs (Fliskmiln Farm, Flisk). There are Barclays at all 3 in the 1851 & 1861 Censuses but no Georgina!
Georgina's age on her NZ Death Cert. may not have been correct. She died in Sunnyside Psychiatric Hospital, Christchurch following a number of epileptic seizures in 1890. I have written to the Canterbury Health Bd to see how I can access her medical record.