Hey Good luck on the interview. I had mine in June I believe my training starts in October, but waiting on confirmation.
First of all be yourself, smile and take notice of what is going on around you. Lots of eye contact. You will have a group assesment (good fun) Maths and english test, believe me I was rahter nervous about these, but just stay calm and read the questions. Be very honest and you will be fine. The interview team are really nice and friendly but very effiecent. Have fun.