I went last week and got lucky!!
There is a 2 on 1 interview that I found a little cold and very thorough.
Have lots of examples of customer service situations to talk about,find out all the info you can about British Airways,the aircraft type,classes of travel etc.
Group excercise was fun,be friendly and include quite members of the group,listen to others ideas and dont be too pushy with your ideas.No tests which I was really happy about.
Overall not a bad day, I had a great bunch of applicants with me and as I sais I got lucky and am now on the waitlist.
Good Luck