I think the thing to remember is that electrical testing is a MUST every 5 years (or more frequent if sites are on the dodgy side) and the LA should do a sensory inspection every 6 months.
If you have the staff, the sensory inspection can be done in-house. Electrical testing of course is the purview of your maintainer.
I do think there needs to be a certain level of pragmatism in the inspection regimes. Full PI’s every 6 months are a waste of time, money and manpower – especially on new sites or those which are in good condition.
Where you have LV sites (and LV pushbuttons in particular) and sites which arent in ideal condition, then naturally it would be most prudent to increase the inspection regime to suit the potential risk.
Blanket, across-the-board, specifications can be particularly wasteful; inspections should be based purely on legal compliance and the condition of the asset (which should be known to the asset owner, recorded, and decided upon from the sensory inspections).