The most important is to be yourself and speak good english. below are some tips:

1. prepare a 2 mins introduction about yourself.
2. prepare a 1 min speech about what you know about RBS
3. prepare to answer that what is the reason that you choose RBS, and the specific position, and why you are suitable for it.
4. prepare to illustrate one or two examples about your leadership experince, and team work experience.

If you can do the above, I believe you can pass. DO REMEMBER to be natural.