Morrisons Local Telephone interview?

I got a call from Morrisons local (as I was walking out of my McDonald's interview :p) and told me that I was successful in the application stage and they would like to do a telephone interview before they call me in. Since I was out, I told them would it be possible to do the telephone interview later as it isn't an ideal time, so they gave me a number to call within 24 hours. I tried searching online and The Student Room for any advice on telephone interviews, however there were none.. What I'm not entirely sure is what they told me.. Whether it was an actual formal interview or a casual interview. Nonetheless, I still want to prepare for it. So, my question is.. Has anyone ever had a telephone interview with Morrisons or any high street supermarkets and have some advice for me? I've pretty much had zero experience with interviews, apart from the McDonald's interview today, which I didn't really prepare for because.. I didn't expect any questions I'd have to think hard about. All they did ask me was, why would you like to work in McDonald's. Thank you in advance. :)