Examples the Bo105 long tail rotor control rod can be installed back to front. The 105 tail rotor can be installed with the flapping stops outboard, found that one on a duplicate inspection.
The tail rotor blades on the 105 can be installed back to front.
Nice idea that no control can be installed back to front but not the case.
As for the CAA requirements, if I remember corectly the Met Police 222 which crashed a few years back had a failure of CAA mandated changes to the tail rotor control system.