Heck Roger, I'm not sure we want that information readily available on the forum!

You might want to remove some of that contact information.
It's always
possible that the key was cloned, but if the dealership ordered a replacement key and there's a third one floating around out there somewhere then they wouldn't have needed a clone kit it at all. It wouldn't make sense to use one if they have a genuine key.
I think your investigations should centre around the dealership's request for a third key and what happened to the one you didn't receive. I believe that's what made the security of your MINI vulnerable.
All the best,
Andrew.