N
Nigel
I see what you mean, but, coding relates to the ongoing safety of the electrical installation, and thus the danger it poses.
If the guidance published by the “industry” says C2, with reasons and explanation, you may have a difficult time justifying a lower code?
Especially when the requirements for this have been implied for many years before it became detailed in BS7671.
I agree that if the guidance states it clearly otherwise it would be difficult to go against that guidance.