I've just emailed Cathay for seats on five flights, used this email address [email protected]. Got window seats on the A330 and upper deck window seats on my two 747 flights. Just told them my flights and dates along with my booking reference. It took about three days to get a reply, but no hassle at all.

Tried emailing Qantas and that was a whole different story, they told me to go back to BA to reserve the seats? why I don't know as they are not code-share flights. So if you do get lucky with Qantas I'd appreciate it if you let me know how you did it. Thanks.