We have not been able to reserve seats on either BA0290 or BA0293 from "Manage Booking" on the website or on the phone with BA customer service. We were not offered the option to book seats when we booked the flight - purchased on BA's website. We were able to book seats on one leg in each direction but not the US-LHR and LHR-US legs.

When we go to "Manage Booking", it says seats will be available at check in. Both times that I called customer service - a week apart - the rep said, after speaking with their supervisor, that there is a "system issue" that is preventing seats from being booked on all flights and there is nothing they can do to help. And that I should check back in 24-28 hours.

Any suggestions on how I can book seats? We do not want to wait until check in; want to be sure that we are seated together.
Do I just need to keep checking online?

Thanks in advance.