That was one of the things that blew me away when I went for my interview. I was clueless, so it never entered my mind that I was the only one there (during my interview) that wasn't on the dole. I came away from the experience with a huge dose of other world reality. It wasn't a side of England I wanted to dwell in.
Nicely dressed, yes, but don't dress like it's a job interview. (I realize the advice is too late, but perhaps future readers with the same question might benefit.) With this group, it might be best to fade into the background more than standing out looking like what the other people in the queue might feel is a prat.
I'm sure they were all lovely people. And anyone can find themselves in the circumstance of being on the dole. My experience may have been unlike anyone else's. It's not a place I ever want to have to return to. I'm talking about the people who were in the queue. The people actually working there were wonderful...and they will never be paid enough.