Of course they didn't stand - his majority is far too big. Only a LibDem candidate could have beaten him, which is why he phoned Nick Clegg the night before he announced his intention of resigning to ensure they wouldn't run against him.
What else is there to be concerned about?? The constituency had a representative already, he didn't 'give up to do something else', just wants to call an election for his own vanity. Ridiculous - should get on being a people's representative (for which he is already elected!).