Never Mind the Buzzcocks/WMG

Preston walking out was a publicity stunt.
During one episode Simon mentions that the BBC haven't received permission to show Paris Hilton's biography, which means that they must have obtained permission to show Chantelle's, therefore Preston/his PR people could have found out and planned accordingly. Also he says it was between walking off and assaulting Simon, and most people also have an "insult" option.
 * Interestingly his apology was a few months after it was announced that Simon was leaving, making it likely that he really was angry at Simon, and the apology was a publicity stunt.
 * Since the apology was as he was releasing a new single, both could be true. The walk-off was to get Preston more attention and the apology was to lose his "twat who walked off Buzzcocks" image.