The offical certificate for the CAA is the MCC certificate which in essence says you have satisfactorily completed the course. You present it for the first multi pilot type rating.
It has been known for "attended" the course to be issued instead where a less than impressive performance was achieved.
The issued certificate is not based on pass/fail.
The JOC element is not regulated by the CAA, and may be embedded into an extended MCC course, or stand alone.
The bottom line is that it is preparing you for the first multi pilot type rating, and the more quality training you have, the easier it will be on the type course, both for you and the trainer.
Those ATOs with links to airlines will recommend the better valued customers.