You're right Mark, where would the A320 go? One option might be a split between MAN and BHX at 3/4 weekly each? The subsequent SNN-LHR is at 12:25, so they could get the aircraft to AGP or FAO and back in time to go to LHR if they scheduled an 0600 departure. Obviously this would work only in the summer and any problems in the Med would put the LHR schedule up in smoke for the day. EI might also have problems adjusting arrivals in BOS or JFK due to slot availability.
This kind of operation would work pretty well from Cork. The LR would be suitable for LHR, AMS or CDG without too much danger to the rest of the schedule, but is unlikely for now. I imagine all but two of the LR fleet will remain at Dublin, flying DUB-BOS and JFK 8 times a day!