Gordon Highlander Tam with 3 Badge Holes - Unit?

[Reid10]

I recently bought a Gordon Highlander Tam found during a house clear out. The Tam is in rough shape, but I actually prefer headgear that have been used. As shown by the pictures, the interior is a yellow cloth (which I have not seen before in a Tam), marked "CPL Sowerby, AC G HQ Coy".

The small size tells me it is likely from the 70s to 90s. I thought it was GH, until I saw the three holes, that go all of the way through. I thought may Aberdeen University OTS, but I believe their cap badge only has two lugs. Maybe for cadets?

Does anyone know what badge (and unit) the Tam might have been used for?

Cheers

Reid