I would imagine that the LGW crew will be hired under the same T&C's as the BFS base crew so therefore there may be no grounds for any action by the Irish based pilots as they have already cleared the new T&Cs for UK bases.
As for Captains, a number of DUB based FO's transferred to BFS for their command, maybe they are expecting something similar to happen for LGW.
Aer Lingus have a few new A320's due to be delivered in the new year. Also the DUB-LGW route is to be increased to 6 per day meaning that they could easily use DUB based aircraft to operate european rotations only with LGW based crew.