You're right not to sign off the CoC but to gather as much info as I can in preparation to installation, inspection and testing of installation. Guess accreditation is not for sale, having said that I'm accredited translates to having read the green/grey book. You've been around for some times and thought that there are approaches. Specifically around earthing systems, I know exactly what it stands for but my challenge is still distinguishing between the abovementioned. Thanks for the welcoming statement.