Originally Posted by KARFA

I think you are just seeing the fare difference upgrade price. If you are offered a POUG it would be reasonably obvious as it shows on one of the banners at the top of the page of MMB, and also down at the bottom the upgrade line would say: Upgrade for £XX per adult

Keep checking MMB every so often though as you may be offered at some point. Just to note if you are not offered one via MMB there is no point calling BA, they won't be able to offer you anything more than what you can see on MMB.