I've been unable to book any reward flights on this route for the last two weeks, I just get an error message. Occasionally I get to see what's there (and LHR seats show up mostly CE and hardly any econ) but can't complete the booking. I'm booking direct on BA.com. Normal BA IT gremlins by the looks of it. I nearly rang up but decided life was too short and booked with Easyjet as the times suited me better anyway.