If slots must be given because of competition then it's likely BA will have to give them up and not take them out of EIs pairs
Aren't Aer lingus the dominant carrier on the route? Not sure why you think it's the British carrier who will be forced to surrender slots. Given the huge competition with the carriers below :
LCY-DUB CFE / WX / BE
LGW/STN/LTN-DUB FR
in the market, none of 'em are likely to want to have a wee go out of LHR. There's not much of a case for making anyone give up slot pairs. In terms of making sure ORK/SNN have access to LHR, genuine question, is it really so difficult to get to DUB and fly from there direct with a US carrier or the ME3?
Very contentious I know, not trying to provoke an argument, keen to know.