The picture is from a book called Bulleid last giant of steam by Sean Day Lewis last published 1968 its has a good section on Ireland , the picture is credited to John Glick who was like Bulleid's assistant I think..
The numbers '2' on the coach doors would have been in red, the 1429 -48 coaches were 70 seaters 3=2 seating no tables and were often called maze coaches due to the layout of the vestibule at each end.