Our call to HMRC on this subject was met with a response that even if director is not drawing a salary but may have benefits or expenses to declare on P11D, then a PAYE scheme would be required and FPS would need to be submitted.
In some situations, for example when the company is semi-dormant, no one would know if a P11D is going to be required. so what do you do. Register or remain registered and submit FPS's just in case. What a waste of time!