Oifig and Phoist, Ráth Maonais - Rathmines Post Office 

1934 - ?

 http://builtdublin.com/rathmines-post-office-upper-rathmines-road-dublin-6/ 

There is an interesting academic study of OPW buildings built for the Post Office in this published thesis:


The Purpose Built Post Office Buildings of the Office of Public Works in Leinster from 1870 to 1947

For details of the 1934 building are see pages 205-213. (Details of the former post office at Lower Rathmines Roadare on pages 198-204.)