all the material had been transferred at the request of Ancestry.com to Auckland
I am astounded. Was this an LDS Church Family History Centre?
I have just done two identical searches, one in the International Genealogical
Index (the online version of the fiche,
which is free to use) and one on Scotland's People (pay per view) for William Low, born in Forfar in 1754.
Both produce two results. The IGI has, in its 'Community Contributed' section, the baptisms of William, son of James Low, on 12 June 1754 and William, son of David Low, on 23 July 1754. I do not understand why these same baptisms did not come up when I did a similar search in the IGI yesterday.
I do not trust the information in the 'Community Contributed' section of the IGI, because although much of it is perfectly accurate, there is a significant number of entries which range from inaccurate guesswork through sloppy research to pure fantasy. So it is always essential to follow up anything you find there until you have seen the original document.
Putting the exact details from the IGI into the search at Scotland's People confirms that these two entries in the IGI are matched by the entries in SP.
The source is given in the IGI as "Family History Library Family History Library , Microfilm : 0820223" and the Batch Number is 7206213, IGI Batch type code.
You have a number of alternative methods for obtaining the original information.
First, you can invest £7 (A$15) in 30 credits at
www.scotlandspeople.gov.uk. This will be enough to view that baptism, the marriage of William to Katherine Mitchell, and the three baptisms of their children that I listed yesterday.
Second, you can hope that some kind person on this list has 30 credits (A$15) to spare, and that they will be willing to use those to look the information up for you.
Third, you can hire a professional researcher to get the same information in the Scotland's People Centre in Edinburgh. I would not particularly recommend this as it is unlikely to be significantly cheaper than doing it yourself.
Fourth, contact your nearest LDS Church Family History Centre and arrange for them to rent a copy of the microfilms (not microfiches) of the Forfar Parish Register for the period in question. I am not sure how much this would cost, but probably just a few dollars per film. When the films arrive, go there and extract the information from the films. This is the method I would recommend, because you can then extract as much information as you like - all baptisms of Lows and Mitchells, for instance, or baptisms of other people's children witnessed by Lows or Mitchells. This is your best chance of a clue to the name of James' wife or Katherine's parents.
There is in Forfar a list of interments in the parish kirkyard, which is where your grandmother's 1957 correspondent* may have found some information. If you wanted to confirm that information you could contact Angus Archives
http://www.angus.gov.uk/info/20369/archives/215/angus_archives and ask them. There might be a charge for this, depending how much staff time would be involved, and if you still have the original 1957 letter it probably won't get you anywhere.
However you could also ask if they have any additional information about James and William Low and Katherine Mitchell. You never know.
One other source which might or might not shed some light is the indexes to the Registers of Sasines. See
http://www.rootschat.com/forum/index.php?topic=26232.0 . However the only way to see these is to go, or get someone to go on your behalf, either to the National
Archives Records of Scotland
http://www.nrscotland.gov.uk/or Angus Archives, as they are not online.
As for James spreading oats, that's not the case. James Low and Helen Butchart had at least 5 children between 1762 and 1770 in Forfar. James Low and Helen Butchart were married either on 2 December 1758 in Forfar, or 2 December 1759 in Dundee, depending which listing in the 'Community Contributed' IGI you happen to decide to believe.
(* Did he actually describe himself as "sexton"? Because if he did, it's the first time I have ever come across that term being used in Scotland!)