Thanks guys. I called and BA quoted £1600 for the outbound leg, for both travelers (so £800 each). Was ideally hoping for slightly less. WT+ is even more expensive as there are only fully-flex fares remaining and as far as I know you can't upgrade an O class economy fare.
Oh well. We've got BA001 to look forward to next year so maybe I'll just have to wait for some luxury.
Once again thanks for the swift replies.