Threads discussing technical issues with the website (blocking searches/booking):
http://www.flyertalk.com/forum/briti...ease-read.html
http://www.flyertalk.com/forum/briti...es-thanks.html
http://www.flyertalk.com/forum/briti...om-issues.html <-- Mostly issues with the pre-Avios site, but it includes newer posts as well.