"Hedga" is House of Edgar.
There is also Robertson Hunting Ancient, available from various mills - mine is from Locharron (where did I put those pictures?). Think slightly more faded than the House of Edgar's Muted.
For a more gray Hunting Robertson, you might want to consider the Hunting Robertson Weathered. It's only available from Locharron in 16 oz., though.

Another source for tartan is the Scottish Tartan Museum. Check the gift shop - the mill which wove each tartan will be listed. I forget how much I saved ordering from the Museum instead of the Kilt Store (it was about four books on CD plus shipping, though).