I don’t know. Maybe it’s a part of British sense of humour. Londoners seems to like using nicknames when referring to some of the buildings and landmarks. Like those in the sketch.
A gherkin, cheesegrater, a knife (scalpel), and the second cheesegrater is under construction. It looks as though London is turning into absurd gigantic picnic table 😂. Maybe Mr. Salt, Mrs. Pepper, and Paprika is on their way.