Here's what people have said about working and interviewing at John Lewis.
What could you bring to the position.
Are you a Customer focused person.
Can you work as part of a team.
As detailed above but you also have an individual assessment where you are asked competency based questions. If you Google that phrase and have some good examples prepared it will give you a head start.
Online application and then group interview
Smart clothes-suit for men and business wear for women.