my NI interview was very short, about 20 minutes and I had my card in a few weeks after that. Except Inland Revenue used my temporary one on a PAYE coding notice and I sent it back, asking them to correct it but thats about it.
I thought the interview would be much longer and detailed and I brought my passport, bank statement, marriage certificate, all the letters from agencies I had signed up with as proof I was looking for work but they didnt need to see most of it. I had to fill out this 12 page application but apart from that, that was it, really.