Airside driving permits
CAP 642 Airside Safety Management is, i believe, just a standardisation of airport safety and airside driving falls into this. To get your airside driving permit you need to take a course and pass a written and practical test which is done by you company, but standardised by CAP 642 and regulated by BAA.
If it's anything like what I had to do at Gatwick you'll have nothing to worry about because it's quite easy. Although i'm not too sure about other companies and jobs. For example, I can imagine that BAA Security (who are allowed on taxiways) would have a more in depth course.