Tony / Colin
Check the RPSI's sales section. I am nearly sure there was a copy of it among the second hand books on the May tour. It's an essential book for Irish railcars giving details of the huge array of types to be seen in the 1950s and 60s.
The AEC cars have been approximately replicated by Silverfox, giving a relatively inexpensive representation, through a re-liveried British Rail Craven 2-car DMU.
(Britain had DMUs, we had "railcars"!)
However, as others have oft remarked, a proper CIE / UTA / NIR / GNR kit or (better still) RTR would be a superb thing to have.
Somebody, somewhere does a kit - I've seen built up examples on this website. I imagine it's not for the faint-hearted to make, and once power units etc have been included probably not cheap. However, we get what we pay for and if within budget, quality is well worth paying for....