I take it this is for bmi.
I was in the same ar situation 2 weeks ago. 2 years junior at LGW. But I was extremely lucky and have been offered a position.
My 2 to 1 was an hour and 5 minutes and covered a lot of areas, from the normal customer service questions through to management techniques and style.
In the end the best advice is to be yourself, be calm and relaxing and try and enjoy it!