Hi Alistair.
I would agree with Dave. Try some more trips closer to home, before heading to France.
We headed off on a long trip when we got our first caravan.
Although not going abroad, we had booked into 8 sites around scotland, seemed like a good idea at the time, but we had to cut down the tour, half way through.
Don't do what we did and over do it, and give yourself time to enjoy your holiday!
Cheers
Hamish C