I'm missing about 330 TPs, and I too struggled with the idea of using a fax...
http://www.flyertalk.com/forum/briti...s-tps-lan.html
So I called the BA Gold line, guy was very helpful said just tell him the flight details and he'll do it all. Great.
Slightly embarrassed email 2 days later asking me to send BPs, eTicket details, Itinierary from travel agent. So I've sent as much as I can electronically in reply to that email.