Bringing a Kit Car to France from the UK

Hi All...hope you're all well

So I'm spending a lot of time in France at the moment, with a lot of free time. I've also got a Caterham 7 kit on order, which will be delivered to my house in the UK at some point in the coming months.

If I loaded all the kit components and chassis onto a large van and tried to bring it across the channel so I could build it at our house in Dordogne, are the French authorities going to try to charge me VAT and/or duties if I can prove it's all paid for etc including UK VAT?

And if the above is possible, what about when I've finished the build and want to trailer it back to Blighty as a completed (but unregistered) car?

I think I know the answer...! But sometimes I am surpised...

Thanks,
J.