A little late in posting here, because I stopped watching K-On season 2 - put it away for awhile and then went back to it on the final months of 2013.
Watched the movie some weeks ago after finishing season 2. It's a good end to the series. they went on a trip, sang a lot, had an encounter with an English owner of Sushi bar, Yui got dizzy in an English taxi. I enjoyed the trip to England part of the movie a lot. Hearing Fuwa Fuwa time at the end of the movie nearly brought a tear to my eye. Sayonara After School Tea Time.
Hmm.. the guy who asked Yui's reason for visit at the airport seems lenient, he did not ask questions when Yui mentioned "side business" as reason for visiting England. XD