Carte Grise for a UK registered motorhome

My husband and I would like to share our recent experiences while trying, but not succeeding as yet, to re-register a British motorhome here in Limousin.

We bought our 2018 motor home from the UK and brought it back to France in July this year observing all the Covid-19 restrictions. As soon as the UK registration (V5) arrived in the post on 28th July, we went online using the ANTS website and applied for a Carte Grise, uploading all the documents requested including a Certificate of Conformity issued by the manufacturers who did the professional conversion on, as it was then, a brand new long wheelbase Peugeot Boxer van. Our timing, on reflection, could perhaps have been better as we were applying just as the August holidays were beginning and, to make matters worse, in the middle of the Covid-19 pandemic. We were disappointed but not surprised to hear nothing of our application, beyond notifications that it had been received and was in the status of ‘Analyse par le Service Instructeur’. So we waited for more than 6 weeks until the day we received a notification that the Certificate of Conformity we had supplied was not acceptable.
We were confused and amazed at this as it is a genuine document produced by a certified and authorised manufacturer and indeed it actually states clearly that the vehicle has been converted to a motor caravan and conforms to the type set out in EU approval no e11*2007/46
 and can be permanently registered in EU Member States. They refused to process our application further and said we had to present it to DREAL for inspection (for a fee of some 86 euros to obtain an RTI (Réception de Titre Isolé).
We completed all the paperwork and gathered all the documents they required, including a very complicated form with calculations of axle weights etc. and we delivered these to DREAL in Limoges personally to save time.
After 3 days DREAL emailed to say the EU type approval no on our certificate of conformity was not recognized in France. Our application was rejected.
Luckily for us, we were able to contact the manufacturers of the van conversion; They are called Auto-Sleepers and are based in Worcestershire. They have an extremely helpful, kind and well-qualified homologation engineer there who does all their certificates of conformity and he has helped us by contacting the authorities here in France to obtain a CNIT(Code National d’Identification du Type) code for our vehicle. Our man at Auto-Sleepers has been doing this for more than 25 years told us that they export 2 or 3 campervans a month and have never had to get a CNIT number to register a vehicle in France. He also said that they really shouldn’t need one anyway; We’re not sure if this has anything to do with the impending BREXIT situation though.
We have now re-applied for a carte grise, armed with this new information and await their, hopefully, favourable response.
We hope nobody else has had or will have such difficulty with what should have been a very straightforward process.