UV protection query for earth cables


I'm seeking confirmation if there is a reasonable engineering response to avoid the requirement for the installation of metal covers as UV protection for large G/Y CPC cables that are installed for external generators and transformers on a metal cable rack system. The cables are 400 sq mm 6491B H07Z-R, and do not have inherent UV protection in the sheath (the accompanying phase conductors do). External portion of cable route is approximately 40m with lots of bends and would be difficult to retrofit with protective covers. I understand there is a requirement to provide UV protection to cables exposed to sunlight, however I would question if there is an argument to claim that the lack of such protection on these large cables would not pose any degradation of their functionality as protective conductors, and that compliance with the regulation in this case would not be reasonably practicable?