Engaging specialist 3rd party’s to assess and approve the safety arrangements of contractors is sadly quite common place these days (its a bit of a money spinner). Many of these companies offer services where they establish complex systems and criteria against which they asses contractor safety management. They collect contractor documentation, review it, go back and forth (driving the contractor crazy) requiring changes, may conduct on site inspections and often issue directions to contractors to satisfy the criteria.
The issue here is that the 3rd party is acting on behalf of the company engaging them and arguably as their agent. As a result, the actions and consequences of those actions may be slated back to their clients. This includes where contractors have been required to change their safety arrangements at the direction of the 3rd party and an incident follows (See Waco Kwikform).
So apart from being a costly and ineffective way of ensuring management of safety by contractors it arguably puts those utilising such services at risk of liability in the event of an incident.