After the meeting if you suspect the company had a shadow
director you should check PAYE was operated correctly on their
salary, and if not, consider whether Regulation 42(3)/49(5) action
may be appropriate
And you should inform the liquidator of the evidence you have found that points to the person being a shadow director. The liquidator will then consider the individual as part of the liquidation investigations, particularly focussing on the reason the person was not named as a director.