Just picked up a book today, Irish Railways: Locomotives, Multiple Units and Trams. It was published in late 2013 and in it it claims that a Mk3 DVT and a few standards and cafe coach are reserved for the West Clare Railway for use with 124.
DVT 6105 and Cafe car 6402 at North Wall, 6301 and 6305 at Dundalk are reserved for preservation.
6306,08 and 13 are at Dundalk, all the rest of the push pull stock has been scrapped already. The 11 other Mk3s at Dundalk are EGVs 7601,12, a restaurant and 8 standards.