OP
SirKit Breaker
BS 7671 are also only guidelines.
if as has been said previously competent persons scheme is happy for it too be used in this way then there are no problems.
BS7671 is only a guideline as you rightly say, but if you go to court and get prosecuted under the EAWR they will ask you why you didn't comply with BS7671, and if you reply "I worked to Napits rules" you are going to have a really bad day out in court, and you probably wont be going home for a while, and i can guarantee napit will say "Nowt to do with us your honour".
Cheers............Howard