Applied and was offered an interview. When I arrived for the interview the store manager was not prepared and told me that their computer system was down, so she couldn't print any of the questions she needed to interview me. She asked if I had any holidays booked over the next year, to which I replied that I did, having 2 weeks booked for the summer. The interview lasted less than 5 minutes in total, and I did not receive a job offer. I asked for some feedback and was told that my availability was not good enough.

Informal, ask questions that you are sent prior to the interview to prepare. Ask about availability and your current circumstances eg. if you are a student etc. and if you have previous retail experience.