My F1

Not done it myself but there a 2 nuts and 2 screws at each of the corners and then it unclips from the back, from what I have heard someone els managed to do it without taking it off. They pushed the clip to the bottom of the diffuser and then twisted it up behind and pushed it further on.
 
mine were a tight squeeze to get on, the bracket rusts anyway, just push them on as far as they go - they wont fall off - unless someone pulls them off. What are the odds ?
 
Looks very familiar. Took the diffuser off to put mine on and tried to hide the bracket to one side but it rattled dreadfully so had to have the bolt at the bottom.
 
Sorry Im slightly (very) confused - you drove to Mallorca??? Whats up with a plane lol! :-p