What's real in the story
They're traveling for a book publisher, I think.
They're sampling food and photographing some landmarks.
There is a touring theme of Byron and Shelley related locations.
But it's not about making the film that they are actually making.
Consequently, they're not aware of the camera, and the impersonations and commentary are not a part of the product that they're making in the story.
I doubt that they stayed in those fancy old hotels where they did the filming. They would probably be at some more normal hotel with the rest of the crew.
Their luggage would not have fit in that MINI Cooper.
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The story is king.