What tartan is that

[M. A. C. Newsome]

Ok, I figured out how to view the original image in a very high resolution (from flickr, right click on the image and select "original" size). That clarifies it. It is definitely NOT MacNab. However, not precisely the same tartan as the one worn in the photo Peter posted, either. In Peter's photo and in the image on the National Register site, the tartan is asymmetrical. However, in the original photograph (from Lochearnhead Highland Games, 2011, BTW), the same tartan is symmetric.

Maybe an earlier or a later run of cloth? One done in error?

But definitely the Lawers Estate tartan, however you slice it.