Thanks, wait until 7 days before then, perhaps some classes of seat can be viewed before confirming on certain routes but the last three or four times we have booked you could not view the seat map without having a locator first.
All our flights have been long haul though, mostly YVR, BA is still our airline of choice despite this plus the squillion or so AVIOS we have earned to date never seem to be available for use on the flights we want!