In 8 BA flights (4 long haul, 4 intra Euro) I have yet to get OLCI to do anything other than OLCI. Seat selection has never been available. Thank heavens I allocated an acceptable seat through my TA when making the bookings. And as for getting that special exit row or aisle seat on check-in, forget it! I'm sure BA EC elites always get these - as do the QF WPs on QF metal.

Needless to say, with booking an award flight BKK-SYD a week prior to travel, I was still allocated a good WHY seat up front with an empty seat next to me (when the rest of the plane looked somewhat full) - so the computer does seem to do a good job for allocations if you have the right colour on the card.