Just a thought if the LHR EDI ticket was booked separately then maybe the person at the front desk was thinking you are only flying economy and dont have access, not knowing that the passenger is entitled to entry because of flying in business class with AA. If the tickets are not on the same PNR this can cause you problems. Mind you after flying across the atlantic on AA, being told to leave because I am a pain in the arse would be nothing compared to the pain suffered being on board an AA flight.