Actually, the tix can be bought NOW. It doesn't work with the pop-up calendar on ba.com but you can type in the dates and it works:
BA302 (from T5)
LHR 06:20
CDG 08:25
BA327 (to T5)
CDG 20:20
LHR 20:45
Seat 3A both ways. Anyone else ?
I've tried that and get this:
The web site can only accept bookings up to 350 days in advance. Please contact your local British Airways office if you need to book for more than one year ahead.