Frequency of inspection

[Guitarist]

GN3 will give you the best guidance, but as the others have said, it's your professional opinion.
The state of the installation, IR readings, even the type of people living in the property may make you think "Hmm, I think this needs checking again in a few years."

 

[Duncan Bennett]

Cheers, all. I've written it up for three years - though i'm pleased to say all the readings came back well within parameters.