The Principal Designer duties CDM 2015 requires, carried out rather than nominally held.
Plans, manages and monitors the pre-construction phase for health and safety: identifying the risks the design creates, eliminating what can be eliminated, and making sure the residual risks are communicated to the people who will build and later maintain the building.
On any project with more than one contractor, appointing one is a client duty under CDM 2015 rather than an option.
Because the duty sits with the client whether or not the appointment is made, and an unappointed or nominal Principal Designer leaves that exposure exactly where the client is standing.
Doing the work properly also produces better information for the contractor, which is worth having independently of the regulation.
Yes, and on most projects it is the practical arrangement — the designer already holds the information the role depends on. It is scoped separately so that what is being provided, and what is not, is written down.
Describe what you have in mind and we will say plainly whether this is the right service for it, and what it would involve.