Originally Posted by
malkie
Top of the page on the MMB booking there is a tick box which states something along the lines of "I have permission to select seats for everyone in my party".
You need to tick then, then do your seat selection

Exactly right... easy to get caught out by this little trap though it's equally easy to sort as
malkie says... and as an F passenger you are fully entitled to reserve your seat at the time of booking.
Surprised the BA agents didn't realise what appears to have happened here... though perhaps I shouldn't be!