Mogga,
Regardless of anything else, you cannot make the existence of asbestos ANY code under 7671 as this electrical standard does NOT cover asbestos.
You should NEVER be surprised by the discovery of ANY asbestos in a commercial premises or any social housing.
The owner MUST provide you with the details of any asbestos present prior to your works else they are committing a criminal offence.
You are also breaking the law if you don't ask for it.
You are correct in that once the material is identified, things differ.
Not many electricians are competent to formally identify asbestos. Also officially it requires laboratory testing. Thus, one must assume asbestos.
One must inform the customer if you suspect the presence of ACM's this is statute law, however, either or both of you are already in trouble by this point!
The information can be attached to a PIR, but, not "really" form part of a PIR and cannot be coded on the PIR.