Hi Al,
Just some comments.
You mentioned problems with ActiveX and ScotlandsPeople. Have you tried Direct Download? Of the three methods, I wouldn't use anything else! I don't know much about ActiveX but I've been told that the access one has to grant to use the other (Java) method is a real security worry.
I am a very stern critic of SP from time to time myself but I have to come to their defence! It's hardly a rip-off to get a certificate with
heaps of information for a measly 6 credits (1 for the search and 5 for the image - one pound 20p) when an English certificate (no search facility) containing
skeletal information costs seven quid! But I have to admit that it is easy to get carried away and spend up big on SP - one needs to be very disciplined in one's searches (i.e. do as I say not as I do

).
The thread 'Optimise ScotlandsPeople searches' by David Douglas is well worth reading. See:
http://www.rootschat.com/forum/index.php/topic,43916.0.htmlAnd always check out the IGI first - for example, the IGI had the exact 1823 birthdate, place and middle name of Alexander, and his parents' names. The extracted entries in the IGI taken from the Statutory Register for Scotland for the period 1855 to ca 1875 are particularly good and can save one from spending money unnecessarily on SP.
On SP, a
free search for Matilda CR*HTON in the 1861 census brings up only one result - and selecting Dundee as the district finds that's where it is. And you now know from Dorothy that this is your Matilda. And you also know that Matilda had left Dundee by the time of the 1871 census (son John born in France in 1867).
As I understand it you were a bit doubtful about spelling variations. Admittedly, spelling had probably pretty much settled down by >1865 (the period in which, according to the subject line, you are interested) but it certainly varied before then (I have about 90 variants - and counting - in one name I'm researching!).
For instance children of John 'CRIGHTON' and Isabel/Isobel/Isabell/Isabella SINCLAIR (all extracted entries from the IGI, all in Angus) appear under four variant spellings -
CRICHTON, CREIGHTON, CRIGHTON, CHRICHTON:
*John CRICHTON, 1821, Eassie & Nevay
*Alexander Nicoll CREIGHTON, 1823, Airlie
*James CRIGHTON, 1825, Glamis
*Margt. CRIGHTON, 1826, Glamis
*Isabell CRICHTON, 1830, Airlie
*William CHRICHTON, 1832, Glamis
*Elizabeth CRICHTON, 1836, Dundee
*John CRIGHTON, 1839, Dundee
In the 1841 census (on FreeCEN - ages of those over 15 supposed to be rounded down to the nearest 5; fortunately this enumerator listed Isabella under her maiden surname which they sometimes did in Scotland, especially in 1841) they appear as
CRICHTON:
Seagate, Dundee
CRICHTON John, 40, Carter, b Angus
SINCLAIR Isabella, 40, b Angus
CRICHTON Anne, 10, b Angus
CRICHTON John, 2, b Angus
I didn't see an Anne in the IGI - and FamilySearch is down at present.
Did you find the deaths of John and Isabella on SP? - which would take you another generation back (if the informants knew the names of their parents, fathers' occupation, and mothers' maiden surnames). If you find their deaths, it would help restrict your census searches. You could also then (hoping that the parents survived until 1855) look for the deaths of their parents which would take you another generation back.
A
free search on SP for the death of an Is* CR*HTON, other name SINCLAIR (married women are indexed under both married and, if known, maiden names) got just one hit. Still in the
free search, refining the year range, age range, and spelling found that this was Isabella CRICHTON/SINCLAIR who died 1868 aged 66 - this might or might not be yours.
I suppose you noticed what might be Matilda JACKSON in the 1841 census on FreeCEN.
Hospital Park 7, Dundee
JACKSON James, 35, Labourer, b Angus
SCOTT Helen, 40, b Angus
JACKSON Barbra Scott, 9, b Angus
JACKSON Matilda, 7, b Angus
JACKSON Janet, 5, b Angus
This might or might not be yours. Though earlier I think you said that Matilda's mother was Helen but that her maiden name was ROSS?? (strange that Alexander and Matilda didn't name a daughter Helen ...).
A
free search finds only one hit on SP for the death of a Helen JACKSON, other name SCOTT, before 1900 (which seemed a reasonable cut-off date). Refining the parameters (still
free) shows that this Helen died in 1880, aged 79. She might or might not be yours. I didn't try other name ROSS.
All the very best,
JAP