Their distinguished guest?

Jack Blake?

"No, no, no," Vivian shook her head frantically. "This can't be." It was probably just a coincidence.

How could a mere chauffeur be a prominent member of the Sky Group, so much so that Mrs. Jenkins had insisted on greeting him herself?

Vivian pondered the possibility, but eventually convinced herself that it was simply a coincidence. But she was a cautious person, and she knew well enough to tread carefully.