I am colour blind. Can I still join the Royal Armoured Corps?

I doubt it will be a problem. You appear to be propanobic - the more severe of the two main types of colour blindness. It used to be a problem when cartridges had colour coded fuses but even thirty or forty years ago I know of incidents when it was simply ignored because they wanted the recruit for his other qualities. You may be short sighted too - the conditions are often linked.