I think you could be entering a pvc minefield here...as you are aware, most new pvc doors come complete with their own frame and locking gear. I wouldn't expect any replacement lock to simply fit in to your door - life just isn't like that, unfortunately - unless you can get a hold of the same make of lock from the manufacturer. Purely my own opinion though - you could call out a professional locksmith for a better opinion.
John
July 2009