our_kinsfolk on Family Tree Circles

I'm at a loss. They married in Mauchline, Ayr, Scotland on 1 Apr 1808. Based on their marriage I'm assuming his birth is abt 1785. Isbell being the same. I haven't been able to find birth or death records for either of them. Have tried name variations and census records but have had no luck. Any suggestions? Are you able to point me in the right direction?