Now 48 track 2

Track 2 on "Now That's What I Call Music Volume 48" is indeed "Pure & Simple" by Hear'say. At least according to the listing on Amazon.co.uk. However, that's disc 1.

There is a second disc in the set and its track 2 is "Stuck In A Moment You Can't Get Out Of" by U2.

Obviously John and Kayleigh had become very fond of each other by the end so I'm inclined to think that Kayleigh meant "Pure & Simple". But the option of her meaning the U2 track does potentially give them something to work with if there is a second series.

Just a thought.