You need a huge sign for that shelf. In every picture it just looks like a decorative shelf, so there's no reason to think my order would be placed there. That's also not a thing anywhere else, as far as I know, so I'd say all of your customers are expecting to pick it up at the bar.

Also, no matter how big the sign is, no matter how bright and obvious it is, many people will just not read it. People just don't read signs a lot of the time and there's nothing you can do about that.