I had to do an in person appointment for my NINo and it's really easy.
Basically the 'interview' is them filling out a form for you. At least it was for me when I went to Nottingham. They do ask you details about your spouse. I think they need their NINo as well. It's been 3 years so I don't remember all the details.
If they asked me if I was looking for work, I just said yes as I was, but they didn't ask me for proof or anything. The only things I took to the appointment were my passport and BRP card. It was a busy office. I honestly think they employee I worked with was happy for an easy form filling exercise.