Cash Delivery drivers with G4S/Brinks etc.

Can anyone give me a list of what is needed to get a job as a cash delivery driver with a company like g4s, brinks etc?
Currently changing my career direction as Im sick of office jobs and I enjoy driving and think that this job would be one Id thoroughly enjoy!
What is needed for this in terms of driving licences? Security course?
I have a degree in transport management but I doubt this is anything they would look for so basically what do I need to do this?