My mother recently booked a JFK-LHR-JFK and during her time over here had also planned a LHR-BCN-LHR with the return to LHR giving her 2hrs 30 minutes to connect back to the LHR-JFK sector. These booking were both with BA but different PNRs.

Well, BA decided to bring forward the time of LHR-JFK leaving only 50 minutes to connect. When I called on her behalf to see what they would do to change her flights they said that there was nothing and she would have to buy new BCN tickets (as non-changeable etc) as they were on different PNRs.

Instead I called customer relations which seems to be one department at BA that always uses common sense. They agreed that the change was BA's fault and changed her to an earlier BCN flight back to LHR. Thank you customer relations.