I am sorry but i very much doubt if Aer Lingus will return to BOH , Ryanair will wipe the floor with them , there is just not the demand here for 2 carriers on the same route
They have already tried the route but unsuccessful a few years ago
I think that Ryanair will however make adjustments to some of the summer schedule soon as they have an aircraft sat on the ground 4 days of the week for over 5 hrs between flights ( ex Gerona route )