Great uncle, but which regiment?

[Advsmt]

Hi, this is my great uncle, David Findlay. He survived but I cannot find a service record for him. He comes from Brechin, Angus so I assumed he would be a Black Watch man. However, no kilt, and it does not look like a BW should title. glengarry could be BW and badge is difficult to pin down.
Anything else I should be thinking about?

Bryan