Hi lor57,
Yes, this is the same line of Laings, your David Laing B.1780 is the brother of my John Laing B.1778 who married an Anne Black.
I had your David Laing - Married to Anne Small with children John, Thomas, David, Elizabeth & Isabell, but didn't have George B.1818, - so I 'Thank You' for that, & have since found him & a second John B.1821.
I am happy to swap info with you, or give more details of the above & fill in any blanks, it all helps.
Mythical