just some info about the photographers and studio in case it assists ...
Lauder brothers (later the business was named Lafayette) started operating in Dublin by the early 1870s, and had several studios in Dublin City. I've been unable so far to locate when they had a studio in Kingstown, County Dublin, which can sometimes help date photos.
Kingstown, now named Dún Laoghaire is a town to the south east of Dublin city and was a major port for traffic to England, and was where the mailboat was based. I've seen a few newspaper reports indicating that often soldiers arrived and departed from here to England.
I'll keep an eye out for detail of their Kingstown studio, and let you know if I find anything
Shane