My Mclaren (via the Airth's) line extends from the marriage of Robert McLaren and Mary Airth (daughter of the Sgt.).
Your mention of the frame brought back memories. The family farm, contained an old attic in which a number of old portraits were stored. The "value" was unappreciated in the 50's and 60's and as a result they were neglected, damaged and eventually I believe tossed out. These were really large portraits in some sort of plaster frames. As as kid, I didn't realize what they were. When I go back, I will see if there are any left. If so, I will take photos (I remember the portraits being about 4 feet high - I'm not sure of the exact dimensions).
My parents still live on the family farm (although it is not the original homestead) in Renfrew Ontario.
And, yes the family is very proud to be descendants of the sgt. I cannot remember not knowing that I descended from him.
Both of my dad's parents (Donald C. McLaren and Marion Stewart McLaren) are direct descendants of Sgt. Airth. However I do not remember ever meeting any Airth's.