Hi Ian, Smith is such a hard name to search for, as you probably already know.
Firstly I checked out the familysearch site for a possible marriage
One possible, James Smith........Helen Henderson married 31st may 1850 Barony. Was this her maiden name? If so, I found the following in 1851 names index, but, this index does not have any birthplaces listed.
Census taken ANDERSON
James Smith age 26
Ellen Smith age 22
Isabella Henderson age 13 quite poss. Ellen's sister
Robert Smith age 1
Also on familysearch there are poss. two children listed
FLORA SMITH
Female
Event(s):
Birth:
26 JUL 1853 Barony, Lanark, Scotland
Christening:
Death:
Burial:
Parents:
Father: JAMES SMITH Family
Mother: HELEN HENDERSON
WILLIAM SMITH
Male
Event(s):
Birth:
10 JUL 1855 Anderston, Glasgow, Lanark, Scotland
Christening:
Death:
Burial:
Parents:
Father: JAMES SMITH Family
Mother: HELEN HENDERSON
If this is 'your' family then William's birth cert. will give you more informatiion, 1855 bith certs. give you the following,
Mother: age & place of birth 1855 only
Father: name & rank, profession or occupation
Father: age & place of birth 1855 only
Parents: date & place of marriage
Siblings: parents' other children, living or deceased (numbers and sex only) 1855 only
Informant: qualification & signature (address if different from location of birth) 1855 to date
Good luck
Liz