Forgive me if this sounds silly and ignorant...

Where does one find out the availability of the classes for a particular flight without actually calling BA directly? I know one can view and select seats upon making a reservation, but I always thought the "booked" seats were misleading, as BA claims they can only pre-allocate 30% of seats before departure (and then EC members get preference for seat selections as they become available).

Or have I got it completely wrong? I always tend to get the seat of my choice, so rarely deal with this sort of thing.

But I would be very interested to know how you found out the availability. Again, forgive me if I sound like some unseasoned traveler... thanks for any hints/help you can provide.