Well one thing leads to another and it does seem reasonably likely that this is my gggrandmother's brother Malcolm's family.
Firstly, the 1951 census records the Kiln Lane Malcolm's occupation as "Shawl Manufacturer employing 25 men and ??5G", a similar occupation to two of my Malcolm's brothers and also his father, who all seem to have been reasonably successful in the weaving industry.
This seems to be the same family in the 1841 census, living in McFarlane's Lane:
Malcome McKetchine 25 Silk HLW
Janet " 25
Janet " 4
Cathrine " 1
Daughter Janet is not with them in 1851 so maybe died or is living somewhere else. However her birth around 1837 ties in well with the 1836 marriage found by Annie.
The second discovery is a cemetery record for a Malcolm McKechnie in Sherbrooke, Quebec, Canada giving birth Jan 13, 1815 Paisley, Renfrewshire, Scotland. That's only one day after my Malcolm's birth date!
Family links included for the Sherbrooke Malcolm are wife Jean Younie and seven children with births starting from 1856. If this is the same Malcolm, it appears he remarried about two years after the loss of his first family.
The 1881 Canada census records what appears to be the same family in Sherbrooke with some additional children's names and the older ones seem to have left home. Malcolm's occupation is recorded as Merchant.
Lastly, there is a Malcolm McKechnie age 37 Trader a passenger on the 'Corra Linn' ex Glasgow arriving New York 10 March 1853. That would tie in with Malcolm being in Quebec sometime before the departure of his family (assuming again it's the same one).
None of this is unequivocal, but it certainly seems a strong possibility that the Malcolm in Sherbrooke is my gggrandmother's brother and possibly the husband/father of the unfortunate family on the 'Annie Jane'. I will dig some more and see if I can find Malcolm's marriage or death record in Quebec that might record his parents name.
Many thanks Allan, Ev and Annie. This has really got the ball rolling again
Regards
Bob