Hi again J.J. and dollylee.
To be quite honest, I got the Jamieson name from information sent to me, likely about 13-15 years ago by a contact who had more information than I did, because I was a real newby at genealogy at the time. Her husband is a descendant of a brother of Scott and Thomas.
I guess I just accepted it as Jamieson.
dollylee is right about how the death registration lists mother (maiden name) as Margaret Jamieson.
Now I have doubt about this. Will investigate further for a different maiden surname for (Scott's) Margaret.
Could it be that seeing as the death registration was certified by David Fife, her brother-in-law, that he only knew her as a Jamieson and that Margaret was her mothers name, therefore gave the name that way? There is no father's name mentioned on the registration.