SIPO has a different take on the matter.
From Radio Kerry
Former TD Tom McEllistrim defends his use of Oireachtas envelopes | Radio Kerry | 96-98FM | Your Voice in The Kingdom
Former Fianna Fáil TD Tommy Mac thinks that he is still entitled to use Oireachtas envelopes despite the fact that he lost his seat in 2011!
He says that FF Senator Diarmaid Wilson gave him the envelopes.