I can't help you directly, but did you know that there is now a 18 Regiment of Foot Royal Irish Rifles Association, email: email@example.com.
I spent the day with them on Saturday at the RBL Wreath Laying Ceremony at Islandbridge and on the way there we stopped at Dr. Steevens Hospital to lay flowers at the grave of 3 men of the regiment who fell in action on 24.4.16.
They are a great bunch of lads and may be able to help you.
Interests:13th Royal Irish Rifles, Banbridge War Memorial
Posted 11 July 2012 - 06:58 PM
The 3rd Reserve Battalion of the Royal Irish Rifles was based in Portabello Barracks as part of the Dublin Garrision at the time. In addition there was also a composite battalion sent to Dublin from Belfast, but I don't have much more detail on it's actually make-up.
I may be mistaken but are your colleagues not from the 18 Regiment of Foot Royal Irish Regiment Association.