Hi
Just moved into a new house and decieded to change all four upvc barrel locks in the doors, done my homework on the web about how to change them.changed three with no problems, got to the main front door, opened it to remove the retaining screw but this was missing, could not work out what was holding the barrel in place, removed both door handles for a better look. Barrel is firmly fixed somehow in the door, the only slight movement is up or down but hardly anything, was thinking about giving it a bash with a hammer but was worried that i might damage something else and would not be able to lock the door at all, the barrel lock is yale if that means anything.
If the multipoint lock strip down the side of the door is also Yale then the cylinder is held in with a grub screw located inside the lock. Try inserting an allen key (3 or 4mm in diameter) into the hole where you would expect the cylinder screw to be and unscrew.
Let me know how you go on with this.
Chris, your a diamond, i would never of thought there was a screw inside,job done 2 minutes flat.
Kind regards
Ian.