Hi
Smelling a nice challenge - I've been beavering away....

I'll post up what I've found, some of which you've just confirmed
Have found some information on other topics:http://www.rootschat.com/forum/index.php/topic,368097.0.htmlhttp://www.rootschat.com/forum/index.php/topic,365452.0.htmlwilliam douglas shennan, occupation toolmaker, son of john shennan, occupation farmer, and mary yann, born 1860 lauriston scotland, married in australia in 1880 to jessie struthers and in 1938 (aged 78) to margaret ruby griffithsImmigration:http://www.records.nsw.gov.au/state-archives/indexes-online/Assisted immigrants arriving in Sydney: 1880-96
Jessie STRUTHERS age 19, on Ship "Samuel Plimsoll", 1880(No other STRUTHERS arriving on same ship, or in the 1880-1896 time frame)
(Age 19, b abt 1860/61)
Found marriage in NSW:Jessie STRUTHERS and William Douglas SHENNAN - 1880 Balmain NSW
http://www.bdm.nsw.gov.au/familyHistory/search.htmPlus 3 SHENNAN births in Balmain to parents named William and JessieWilliam J - 1881
David D - 1883
Robert - 1886
Another forum says William SHENNAN and Jessie STRUTHERS had: They had 4 children, 4 boys and then a girl (sic - that adds up to 5?)
The girl was my grandmother she was born in 1894 in the State of Victoria, here in Australia.http://boards.ancestry.com/surnames.shennan/1/mb.ashx
The following looks very likely to me
IGI has the following submitted (therefore caution) marriage:
William STRUTHERS and Mary CROSS
Married: 14 March 1857 Bothwell Lanarkshire
IGI has the following extracted births of children to parents named as above:William STRUTHERS - 12 Jul 1855 Bothwell
Alexander STRUTHERS - 3 Jul 1857 Inverkip (Renfrewshire)
Mary STRUTHERS - 1 Jul 1859 Bothwell
Janet STRUTHERS - 21 Sep 1860 Bothwell
Catherine STRUTHERS - 5 Feb 1862 Bothwell
John STRUTHERS - 6 Jan 1864 Bothwell
James STRUTHERS - 16 Deb 1866 Blantyre
Allan STRUTHERS - 19 Mar 1872 Blantyre
CENSUS (the children on Census who match births on IGI have been
highlighted)
1851: Uddingston, Bothwell, Lanarkshireparish: 625, ED: 4 / Page: 13 / HS 43
Head: William STRUTHERS 26, Master Carpenter Employing 1 Ap., b Blantyre
Wife: Mary 23, b Bothwell
Dau: Ann 1, b Bothwell
1861: Uddingston And Bellshill Rd , Uddingston, Bothwell, lanarkshireParish 625/1, ED: 4/ Page: 11/ HS 58
Head: William STRUTHERS 36, Joiner, b Blantyre abt 1825
Wife: Margt 33, b Uddingston abt 1828
Dau: Ann 11, b Uddingston abt 1850
Son: William 5, b Uddingston abt 1856
Dau: Mary 2, b Uddingston abt 1859
Dau: Janet 6mths, b Uddingston abt 18601871: Kilbride Road, Blantyre, Glasgow, LanarkshireParish: 624 ED: 5/ Page: 4/ HS 95
head: William STRUTHERS 46, Master Joiner Employing 3 Men & 2 Boys , b Blantyre abt 1825
Wife: Mary 42, b Uddingston, Lanark abt 1829
Dau: Ann 21, b Uddingston, Lanark abt 1850
Son: R-----?? 19, b Uddingston, Lanark abt 1852
Dau: Elizabeth 17, b Uddingston, Lanark abt 1854
Son: William 15, b Uddingston, Lanark abt 1856
Son: Alexander 13, b Gourock Renfrewshire abt 1858
Dau: Mary 11, Scholar,, b Uddingston, Lanark abt 1860
Dau: Janet 10, Scholar,, b Uddingston, Lanark abt 1861
Dau: Catherine 9, Scholar, b Uddingston, Lanark abt 1862
Son: John 7, Scholar, b Uddingston, Lanark abt 1864
Son: James 5, Scholar, b Uddingston, Lanark abt 1866http://genforum.genealogy.com/struthers/messages/14.htmlSomeone descended from James STRUTHERS, the son of William STRUTHERS and Mary CROSS who was b 1866
Cheers
AMBLY