I got housing benefit when I graduated (am musician). I worked a few hours a week as a lecturer and the money for that cancelled out my dole, which was fine by me. I just couldn't get enough hours initially to be completely self financing. However being a waiter could have meant that my training was completely wasted, as I would have had to turn down the few gigs I was offered so as to be reliable in a job I wasn't trained to do.
However unless things have changed you were allowed to only apply for things you were qualified for - so I used to show up and honestly say that I'd applied to the Halle Orchestra or for an arts admin job, and then declare my lecturing income and be on my way.
They never even tried to get me a manual job, almost to the point of obstructiveness.