Quote: "
Terminal 1 in Heathrow is due to be demolished in 2014, so a change was inevitable. The open question was whether it would be the new Terminal 2 or Terminal 3 where Aer Lingus ended up."
Not LHR-3, there is no common travel area/domestic arrivals facility. LHR-2, being purpose built, will have this available.
AFAIK, LHR-1's occupants are due to move to the new LHR-2, along with the remaining Star Alliance carriers still in LHR-3 (AC, SG, SK, TG, TK, etc.) and LHR-4 (ex-CO part of UA). Then LHR-1 will be demolished, re-aligned, and rebuilt as an extension to LHR-2.
Does this mean that AC and EI will use LHR as a sort of "scissor hub"?