Hi Jo
I don't pretend to know anything really, but I'd suggest that this gentleman was perhaps in a Scottish Army battalion, as his cap looks distinctly like a glengarry. If you google glengarry, wikipedia have a no-nonsense brief history - I dont' always believe everything from wiki, but this looks to be correct. For a period in the late 1890's I understand that the glengarry did not have a chequered band, but still had the feather, which your chap appears to have. You might be best posting a link on the Forces forum to get someone who really knows what they're talking about, as I may have got it completely wrong!! But it would explain why he was in full dress for getting his piccy taken

Also, and again someone will be able to tell a lot better than I, but I think there was a photographer Whyte & sons in Ayrshire if my memory serves me......
Fine figure of a man

Lass x