I sent the email i received from Mercedes Uk to the contact in France i have been dealing with and just had this reply.
If You want to register a van in France you have to prove that your vehicle is conformed to the french law.
We only can produce such a document.
This Is not a COC as it is mentioned below.
If You want This document you have to sens us a complete formular.
Can anyone cast any light on this, i thought from reading up on impoting and registering a vehicle in France i needed the CoC, now Merc France are stating i dont need a CoC but need to complete the forms they have sent me and send them the €350 to get the certificate that isnt a CoC