Morning Mark

I think you should think about this in terms of the "CDM" Regulations where you are the (non-domestic) client who will bring in contractor(s) from time to time to carry out construction work on the roof.

All words in italics in this posting are defined terms in CDM.

At different points in time, the construction work would include maintenance of the solar panels, maintenance and examination of the "mansafe" system and whatever needs doing to the roof itself.

It is quite possible that the "mansafe" system is not designed for all potential roof maintenance operations, that may require access towards any open edges (and/or any fragile components such as roof lights).

Unless your own employees are going up on the roof, then the primary duty of care under WAH (inclusive of rescue plan) rests with those employers you contract to do what is needed on the roof.

But, CDM requires you as the client to provide any contractor(s) (or those tendering for work) with pre construction information - much of that should be in your health and safety file for the structure in this case, the building.

Whether or not you actually have a health and safety file, as such, you should have information about the "mansafe system".

Some of the works to be done may be so limited in scope that you do not need to appoint a principal designer or principal contractor, or end up assuming the roles of PD and/or PC if you don't make the appointments but this does not remove many of the duties on the client under CDM.

So, I would be asking the contractor to give details of how they intend to do the work in compliance with relevant health and safety legislation - a construction phase plan, however titled - so it might simply be e.g. a method statement that includes details of the rescue plan.

I am presuming that your organisation's business is NOT construction work, let alone doing things on roofs, so why try and second guess the specialists you are to contract these works to?

NOTE - those doing e.g. routine examination of the "mansafe system" may well argue that the work is not construction work. I would disagree, for reasons of case law interpretation of components of the definition of construction work but I am not going to going into detail in this posting, as......

Whether or not some tasks on the roof are construction work, exactly the same principles could be applied to enable compliance with your duties and those of your contractors under HSWA and the Management Regs.