Twistedfirefighter
I have another suggestion to throw into the pot. So you had that slot on Saturday night at Palma. Well, I happen to know that there were a lot of aircraft headed for Ibiza that night. There was a whopping great thunderstorm over the island and a lot of metal ended up diverting to Palma. Many were stuck for a couple of hours before the storm moved away from the airport and aircraft could get back over there.
This, I would think, could have caused some screw ups with slots. All those aircraft going IBZ-PMI and back again, and then IBZ to the UK, probably on the same routes as the PMI crowd heading back to the UK.
Just a thought.