Does a "shadow director" have to complete a P11D

The tenant had been living in the property since the Company first rented it out 2 years ago and is not related to the previous director. A P11D is due for 6 months from the date of appointment but I am questioning whether in fact she was shadow director and therefore may be required to complete a P11D for the full tax year.
I have only just been made aware of the situation after receiving the paperwork to prepare accounts. The tenant/director is not happy as you can imagine at having to pay tax even for the 6 month period. (If only clients would get advice prior to making these decisions)
I am inclined to just raise it from the time she became director but not sure how HMRC would view it?