So troubled, I rang NHBC to enquire about their amendment of guidance in 2016, i.e. why & where from? They said it was more realistic, and from consultation with their members and partners?
I also rang Elecsa, who said it was still 300mm yada yada. I've emailed Electrical Safety First, to see if they can sink this one with a counter work top argument.
I've had a bit of a boring day
As I'm still getting 'hits' from my post, nothing in terms of a reply from ESF, as yet