So we lost the house keys, whoop, and I'm having to replace the locks. It's a typical EuroLock and all was going well...until it came to putting the 'fixing screw' in place for the new lock.

There re appears to be two small cylinders ontop of each other with a nub on each that is blocking the fixing screw hole on the door frame and the hole in the lock...I've tried pushing them out of the way with Allen keys but while they do seem to spin nothing changes and no gap becomes available.

Anyone know what these things are and how best to get rid of them?