Can you learn multiple skills in the RAC, like sniping and Ajax driving?

there is opportunity to get on to a sniper course, as well as many other courses, Ajax driving will soon be rolled out through several regiments, currently you can still learn to drive the CVRT, Warrior, Challenger 2 and the Jackal all with the respective regiments. As for other courses, there is the PTIs course, P company, farriery, Horse riding instructor just to name a few.

Can you double up and have more then one of those skills?? Can I go on multiple different training courses?

absolutely. if there is time in between your working pattern put your name down to get on as many courses as you can. You will be given a thing called learning credits and these can be used on almost any qualification. Just be sure to go through your chain of command and ensure you can have the necessary time off to complete the course.

Do you have a set number of credits then?? And once you’ve used them all up are they then gone, or is there ways to earn more? Or am I completely miss understanding army credits?

you get given learning credits yearly as a standard and im not aware of being able to earn more than what is given to you.