Could you have c's and still be a vet?

Yes some vet schools do a foundation year for students who got c's at A-level. These courses are called 'gateway' or 'foundation' courses, and you do an extra year before starting the actual vet course where they catch you up with the people who got a's. Another option is doing a vet science degree before doing a vet medicine degree, so you end up with 2 degrees at the end of it all. After doing a vet science degree many vet schools have an accelerated vet medicine course where you only have to do 4 years more to become a vet.