It was awarded for the best exhibit (Grand prix) at the London 2010 international stamp exhibition.
A picture can be found on the last page (page 45) of this document from Palmares. You will need Adobe Acrobat to open it.
Another email from Ian Rose.
"On your blog you note that Glen Morgan has asked (of the recent self adhesive prestige book pane):-
And will there be a different version in the PSB to those used on the covers?
I have only seen a couple of the panes intended for first day covers, but there was one of each of the two types described by Ian in his post. For what it is worth, I did not see any differences between the panes intended for first day covers and the panes that were in the prestige booklets."
Thanks also go to Ian for his comments.