IIRC,
the original planning permission from 2007, first submitted in 2004, was for 3,100m. Since then, the DAA has moved to a preference for a 3.660m build.
see the Capital Investment Plan 2010-2014
http://www.aviationreg.ie/_fileuploa..._2010-2014.pdf
section 8.1.3 Physical requirements of new runway, Page 51.
JAS