fieldpiece

Here's a possible name. Wicklow News-Letter and County Advertiser - Saturday 28 October 1916:

Bomb, and Acting-Sergt. A. Baker, clerk. R.F.A., Ballincollig, was found not guilty at court-martial at Cork on charges of having applied £5, the property of his commanding officer to liis own use, suppressed correspondence, applied to his own account moneys paid him for the purchase a wreath, and being unfit for duty owing to indulgence in drink.

Which one has the guilty innocent look?

There are still Barracks buildings at Ballincollig, a former cavalry barracks Streetview, but I don't see this building.

And in the same newspaper on March 18th:
Saturday 18 March 1916:

A protest against the action the Crown in remanding again and again Corporal J. W. Brodie. R.F.A., Ballincollig, on charge of bigamously marrying Hanna McCarthy was made by Mr. O’Driscoll, solicitor, at a Court in Bandon. Accused was again remanded.

I spent four years in Ballincollig (1 FAR) I don't remember the building in the background, or anything resembling it.

Not Ballincollig in 1916, but the 30th Reserve, RFA the previous year. Hull Daily Mail - Wednesday 18 August 1915:

ARTILLERYMAN'S DYING CHILD. Thomas Henry Keeley, 31, of Sultan street, Camberwell, driver in the 30th Reserve Battery of the Royal Field Artillery, was charged with being an absentee from Ins corps since Sunday last. When arrested by P.C. Hansford, the prisoner said the reason he did not back was that had a child lying very ill in Belgrave Hospital. Mr Biron committed the prisoner to await military escort. The prisoner, mentioning that the child might die at any moment, asked that he might allowed to visit the hospital before he was handed over to the military authorities. " We will try and manage that for you" replied Biron. His worship gave instructions the police accordingly.

Isn't that the same moustache as the one on the left of Monday's photo?

From 1913 Fox Greenhough & Co's premises in Kilkenny were 'in the street facing the Canal Square', Mr Greenhough having acquired a long lease for the shop, and remodelled it completely, with 'a comfortable and commodious reception room', and new facilities for developing and printing not only the firm's work, but also that of amateurs. No movable boudiour, though. (Kilkenny Moderator - Saturday 05 July 1913)

I think it might be this building . The article in the Kilkenny Moderator mentions the new recessed windows, so that people standing looking at the windows wouldn't obstruct the narrow pavement. PS and the article said it be noticeable when crossing John's Bridge.

Fox, Greenhough & Co were equal opportunity employers. Not fair to incompetent people, though.
. (Kilkenny Moderator - Wednesday 17 December 1919)

Probably outside the 'circa 1912' date, but Kilkenny Moderator - Saturday 20 February 1915 reported:

ARRIVAL OF FIELD GUNS. During the week nine 15-pounder guns arrived in Kilkenny for use in training the R.F.A. Battery now stationed here. Much interest was evinced in the arrival of these deadly weapons of destruction. We also understand that about 300 horses are expected to arrive during the nest few-days, and that they will be quartered in St. James's Park.