One of the benefits is that they run some great lectures on rodentology. Luckily, Gina, the lady who runs the BAR training courses for the CCT lives really near to me and also looks after my piggies when I go away. I have been to lectures on dentistry, skin, respiratory diseases and emergency first aid. I hope to go to some more this year. If you want you can even do the full rodentology course.
I must admit i'm not too sure about the services the CCT offers although i'm pretty sure registration includes free advice and free check-ups for your piggies (probably more useful if you live in the cambridge area or near a rodentologist). I'm sure if you e-mailed Gina or gave her a ring she would be happy to chat with you about the services the CCT provides ;D
Alex x