I am fairly convinced re the answer but am following the CIS queries with interest. An electrician has a gauffer. The firm does some work for contractors and some work in private homes. The gauffer does have the freedom to say he isn't available and the boss might say he isn't required. The boss assumed that the gauffer is CIS as they are "in the construction industry" but I think he can just invoice the firm without CIS as the firm does mixed work.
Is it OK not to apply CIS?