So at some of the theater’s in London (and I’m sure in other places in the world) you place your order and pay for interval drinks before the show starts. This way when it’s time for intermission, your drink is already ready for you and there is no line. Very civilized :)
It’s just coincidence that it’s in “position L”, that was already on the sheet when I scribbled my name on it. So when I went to get my drink there was my bottle of Schweppes, a glass with ice and my order sheet (see attached photo).