Hello! - does anyone know how to remove the lock barrel from a sliding door handle? I've got a broken handle (with a key) that I would ideally like to replace with an intact handle (locked and without key - can't see a code on the square section) - my rather basic logic was to 'simply swap the barrels over - been scratching my head for ages now trying to see how the barrels come out - can't see any grub screws or similar - any ideas?