Try calling the BA reservations desks to do an award booking. I found that the reservations desk had flights that were not showing up as available online when I was searching for a few upcoming flights (RT LIM-CUZ and a one way from LIM-EZE in J). After they tell you there's availability, tell them you've been trying to book the flight online for the past few days but the website keeps crashing before the booking is completed, so can they waive the booking fee. I've yet to have an issue by doing this. Even if they won't waive it, it's not a huge deal if you can find the flights you want (I think it's like $25). Just a thought.