its an easy interview
there will be 2 people there, one interviewing you and one assessing the interviewer
they ask you basic questions i.e. what would you do if a customer did this, etc
they'll give you a basic mental arithmetic exam and give you some simple odds questions, i.e. if you bet £10 on a horse with 7/1 odds what is the return? return is £80, £70 win and £10 original stake
it's not a hard interview and if you can't get the job then there's something completely wrong with you. i've seen absolute retards during the training days (i worked there for over a year)
if successful they tell you you're hired on the spot (was in my case anyway)