I will presume when you say "just now", you mean you were at the airport desk dropping a bag or similar, and at this point you were issued new BPs with the changed seats?

The Duty Office will not be able to help at this stage, as the flight seating will be under airport control. Only the check in desk or gate could change it now.

Looking at the flight, assuming it is BA2625 today, it's completely full down the back - not a single spare seat to be had. So in terms of getting your exit row seats back, I would say there is nothing to be done unfortunately.

I would put in a post travel complaint. While BA are clear that seating is never guaranteed, they do seem to throw a few Avios at people who complain about such moves. It could be we've seen yet another example of the curious changes as discussed here: Bumped from my seat : being moved without reason or notification, ongoing issue - FlyerTalk Forums