I guess then that the birth of Katherine recorded in Falkland stands a good chance of being yours.
SETH, Katherine Christening
Gender: Female
Birth Date: 15 Jan 1814
Christening Date: 6 Feb 1814 Recorded in: Falkland, Fifeshire, Scotland
Father: Andrew SETH
Mother: Ann LEVEN
Yet I'm not finding a James record anywhere!
So let's look at the 1841 census where you think you have Andrew and Ann. I'm assuming this might be the family you're looking at???
Name: Andrew Seath
Age: 65
Estimated birth year: abt 1776
Gender: Male
Where born: Fife, Scotland
Civil parish: Dysart
County: Fife
Address: Strathove
Occupation: Farmer
Parish Number: 426
Neighbors: View others on page
Household Members: Name Age
James Halden 19
Cathrine Haldon 2
Margaret Haldon 24
Thomas Haldon 30
Jean Henderson 19
Andrew Seath 65
Ann Seath 60
Thomas Sinclair 16
and if so.....well.....Andrew's death
is found after 1855

at which time it states he's a widower and his grandson is the informant but it does not state who he was married to!!!
Here they are again in 1851 minus Ann
Name: Andrew Seath
Age: 82
Estimated birth year: abt 1769
Relationship: Father-in-law
Gender: Male
Where born: Kinglassie, Fifeshire
Parish Number: 424
Civil parish: Dunfermline
Town: Pitcorthie
County: Fife
Address: Pitcorthie
ED: 3A
Page: 12 (click to see others on page)
Household schedule number: 57
Line: 16
Roll: CSSCT1851_87
Household Members: Name Age
Helen Balfour 18
Janet Blackwood 23
Agnes Halden 10
Alexander Halden 10
Catherine Halden 12
Isabella Halden 5
Margaret Halden 41
Margaret Halden 8
Thomas Halden 40
Andrew Seath 82
So now the trick seems to be to try and find out who this Andrew was married to. We'd like to think it was an Ann....but Ann who???? I thought sure I'd find a DC for Margaret under Seath and H*ld*n and it would be over for us....but not so easy. So here is the Halden family in 1861....
Name: Margaret M Halden
Age: 50
Estimated birth year: abt 1811
Relationship: Wife
Spouse's name : Thomas
Gender: Female
Where born: Abbotshall, Fifeshire
Registration Number: 424/2
Registration district: Dunfermline Landward
Civil parish: Dunfermline Landward
County: Fife
Address: Farm Of Easter Pitcorthie
Occupation: Farmers Wife
ED: 4
Page: 11 (click to see others on page)
Household schedule number: 56
Line: 17
Roll: CSSCT1861_55
Household Members: Name Age
Alexander Halden 19
Cathrine Halden 21
Isabella Halden 15
Margaret Halden 16
Margaret M Halden 50
Thomas Halden 52
Maggret Heir 21
Robert Heir 15
Elizabeth Hutton 25
Agnes Robertson 19
Henry Stark 17
and note that Margaret states her place of birth as Abbotshall which doesn't help a whole lot as it's not particularly near Falkland to tie in with the Katherine and it's not particularly near Auchterderran to make this birth below qualify as hers....
MARGT. SEATH Pedigree
Female
--------------------------------------------------------------------------------
Event(s):
Birth: 08 MAR 1811 Auchterderran, Fife, Scotland
Parents:
Father: ANDW. SEATH Family
Mother: ANN TAYLOR
so back to hunting SP for Margaret's death....and after thrashing about....
finally here it is...
1875 HALDEN MARGARET MOODIE ROBERTSON F 64 DUNFERMLINE LANDWARD /FIFE 424/02 0179
but it says she had been married first to a Robertson and her maiden name was Moodie!!!!!!!!! So how can Andrew Seath be a father in law to Thomas Halden in 1851????????
I don't think this is helping......
Anyone got some further ideas on this one??????
Best wishes
Jean