Is the new drivers CPC just the same as the managers CPC?

No, they are completely different things.

If I go for a B+E test do I need an Instructor with me or can I just turn up on my own?

You will need a person with you who has held this category of licence for at least 3 years.

volvo fh12

Do I need to pass a medical and theory test before taking a B+E test?

You will only need to have a full Category B licence prior to taking this test. A medical and additional theory test are not required.