We do, indeed, and that really illustrates what I'm saying. They surely say that because (as you usually point out to them), they don't understand exactly what 'Part P' is - surely NOT because they believe it would be correct to say "It's not in a {kitchen|bathroom|garden} so there is no requirement for the work to be done safely"?We see the bald statement all the time, "It's not in a {kitchen|bathroom|garden} so Part P does not apply".
In other words, I believe (you may say naively) that everyone understands (or presumes) that there is a requirement for all work to be done safely, regardless of what they do and do not understand about 'which bit of the legislation says what'.
Kind Regards, John.