corporate-wage-slave

Personally I would let this one slide. EC261 exists as important consumer protection, and it came about due to some airlines being beyond cavalier in their approach to irrops. Here BA may well have got it wrong on the CDC card, maybe the clock was running down to ensure an ontime departure, but BA did have a good reason to be cautious about the lack of documentation. What they did next was to fix their mistake fairly quickly and get the passenger on their way, albeit with a few hours of delay. Companies make mistakes, we all do, but it's how they fix their mistakes is the key thing. I have no doubt that if the OP pursued the matter at some point s/he could extract some money by way of compensation, but given the context I would see that as secondary to getting the trip completed. If BA had essentially abandoned the OP then they would deserve both barrels, but in the circumstances, given an indirect routing, I think this is what we have to endure at least for a few more months.