Applied through their website and got a call from an external company who dealt with the apprenticeships who asked me the standard questions like are you available to 5 days a week etc. Then if that was successful they pass your application onto the General Manager of the restaurant you are applying at and if they are interested they will invite you for a 1:1 interview, I wore a full 3 piece suit which seemed to be acceptable.
In my 1:1 interview they asked me questions like, how would you deal with the challenges of being a young manager, looking after older staff? And, what would you say a shift manager does? After the interview he invited me for a session to assess my abilities to interact with the staff and to see what kind of things I picked up on to see if I was manager material.