What Happened to the Christmas Party Invite for Ade?

The most senior civil servant in the country, a his office team sent out an invitation called christmas party invite for ade on the seventeenth of december during lockdown. Now we understand this event was a virtual quiz. Most of the staff were sitting at their desks. Apparently there ware at least six people in the room having some drinks and snacks while the virtual quiz was carried out. And mister cas apparently walked through the room at one point because he to get to his office that way. However, what this means is that simon case, who's meant to be the person investigating whether there were whitehall parties, actually knew about a whitehall gathering which took place outside his office