Watching this from the outside.
What would happen if you had moved from Germany or Spain, which I gather have a lot of firms offering van adaptations, having already owned such a vehicle registered there and wanting to bring it with you? Wondering if it’s already registered with that fitout before you bring it would make things easier.
I guess it’s no different to a British company doing it , but possibly helpful that it’s within the EU and no extra tax to pay. I did wonder if I’d got certain things done before putting mine into French plates if that would have been easier… most things can still be done in France, just tighter rules and expensive workmanship and more limited choice of products like poptop and seating from what I gather.
with regards obtaining vasp for a custom campervan - after looking into it, the process looked horrendously complicated to me and I would suggest is probably almost undoable for most normal mortals. my french is fluent but the paperwork involved is vast and knowing all the ins and outs of the requirements, and having a relationship with your local dreal office seems essential. hence my conclusion was that the only way was to pay a specialist van builder to do the whole thing. someone who is doing this process regularly. I found several who would do this for me. the going rate just to get it thru VASP was around 900euros.
my guess would be that the french dreal would still not accept any work done in spain or germany, despite those countries being in the EU. they appear to insist on a french company doing it.
What makes you “guess” this?
Why only custom camper vans?
They are just preferable to caravans.
speaking to multiple french van conversion companies who confirm that this is the case.