We used Aer Lingus for the 2 for 1 from LAX to Ireland. Aer Lingus offered nonstop flights from several us gateways, so we couldn't stop over at London. But, we did fly over to London from Shannon on our own via Aer Lingus. Its ireland-london flight was short and the diff between business and coach was hardly much. So, although we flew in business to London, I wouldn't recommend to spend xtra for that. Ok, if anyone knows 2for1 to Ireland and can stay over London, I like to know it too. Thanks.