He called his tartan by his regimental number, and that was that! Many of our traditions about clan tartans began life with the uniform tartans of the regiments, and the close associations between regiments and certain clans...
The regimental number went out with the Cardwell reforms of the British Army in 1881, but that didn't stop a lot of the old soldier's from using them.

Cardwell's reforms amalgamated a number of regiments, and caused mutch bitterness; For example, the 75th Foot became the 1st Battalion, the Gordon Highlanders, which was not a popular decision:

Epitaph on the 75th, 30 June 1881

Here lies the poor old seventy-fifth,
but under God's protection,
They'll rise again in kilt and hose,
a glorious resurrection!
For by the transformation power
Of Parliamentary laws,
We go to bed the Seventy-Fifth,
and arise the Ninety-Twas!

from Mr. Kipling's Army by Byron Farwell.