They can use what they like, as long as they do not start picking and choosing and then referring to is as a British Standard.
If BS7671 is used to claim compliance with P1 then it should be in full.
If only scraps of it are used then it is up to them to show how it meets P1, but it is no longer meets the requirements of the british standard.
If BS7671 is used to claim compliance with P1 then it should be in full.
If only scraps of it are used then it is up to them to show how it meets P1, but it is no longer meets the requirements of the british standard.