You need to have passed all the CTs and CA1 now to sign up for CA3. There is not an exam any more, just a 2 day course. (I think this is a bit unfair, especially given you're likely to have to wait 6 months to get on a CA3 course, and another 6 months to take in again if you fail).
For CA2 you need to have passed all the CTs, including CT9 to sign up.