Was on the return from MAD on the 24th too, for my first A380 flight, which I loved, perhaps looked like luxury vs my Iberia / Level A330 in the morning.
Just a data point for my experience of a non B2B Madrid daytrip. I flew out on the IB3163 from Heathrow (leaves at 10:30am), with the aim of getting a few hours in Madrid at least before heading back to the airport. Left around 1 hour 20min late due to EXTREMELY slow document checks during boarding and a missing pax (delays on this service don't seem uncommon). Got a Level A330 sent (no proper biz class, just PE), lots of irate pax about this, full flight and delay made for a cramped and tense atmosphere.
Arrived after a number of South America flights due to delay and it took nearly an hour to clear immigration (never seen it so bad), and then as you'll know, a lot longer to reach the trains towards the city. (We decided not to go in the end).
BA A380 on the return great although crew somewhat functional rather than friendly. Speedbird cafe order not loaded either after chasing the crew an hour into the flight after I saw them serving paying passengers... Pretty abysmal on that front considering how far I ordered and the size of the order too. (I got nothing at all - bar the usual water & crisps).
Sorry to hear about the case issue on this flight too!