Over many years I have see a lot of capable people through accreditation on these topics.
Sectors in which I have worked on accredited coaching and mentoring include:
Construction Local Government The NHS Technology Universities Retail Management
The first two below are mandatory, then if the coaching route is taken, the folowing two complete the Certificate.
Thirty six hours of workplace coaching with at least three learners is at the heart of the accreditation process.
These need not be used, but they do lay out very clearly what is needed if using conventional written assignments for assessment.
Again, these mark sheets best fit a conventional written assignment, and there are many other assessment methods.