In reference to the airline forcing you to fly a shorter route, I flew SYD - JFK - MIA - EZE - SCL instead of SYD - SCL non-stop. I find that airline reservationists only know the routes for their company so getting a long routing approved for a LHR - SCL route by BA may be hard but not from other carriers. Just read them the list segment by segment and tell them you are meeting clients in each place for a quick meeting.