To be honest, UBS seem overly nice about dishing out work experience to lots of random people. A number from disadvantaged local schools come-by and every so often and intern gives them a tour of the floor as it were.
It's kind of embarassing for the intern when one of them goes up to someone and blurts out 'how much do you earn' and then finishes it all off with 'do you think I will get in, I've got CCC at AS level'. Maybe the person has got something in there which will make it work, I don't know, I'm going off what a tour person has said (not done one myself).
But yeah, deep down, UBS are generous about that kind of thing. But I still don't think it really adds value to you or allows you to show yourself off.
There are opportunities within your school or uni to show you are amazing. And you can certainly create those opportunities and fill them yourself.
If you're finding it hard to find something about yourself to 'sell' to someone, I think it's fair to say that you're going to find it hard to get into the industry and persuade people you are the person they want to work with.