We used to holiday a fair bit in Southern Brittany, the Vendee and the Royan area, so on the west coast but not quite as far as Biscarrosse, if that's the La Rive site you mean.

We used to get a Western route ferry. We tried various combinations of going via Plymouth or Portsmouth and taking overnight or early morning ferries. We decided the best way was to stay overnight at the Travelodge over the roundabout from the ferry terminal at Portsmouth and take the early sailing to Caen. In Caen you're pretty much straight onto the major road network. Have a look at a route planner - you may find it quickest to use some toll roads, so read up on payment methods.

I would advise not travelling down through France on the nightmare middle Saturday of August (13th this year) when the whole French population seems to be travelling to or from their holidays.

We always had to look at what the children would like, i.e. waterslides and activities off site, but I recall the following being a success.
Les Biches in the Vendee (Flower), swimming pools and water slides were very popular, you have to drive to a beach, within easy reach of two towns and shopping.
La Pinede, near La Palmyre. In fact we went to La Palmyre twice. When the kids were teenagers they went for surfing lessons five mornings in the first week, and there are loads of activities - a zoo, quad bikes, woodland ropes, horse-riding...

There were others, but I can't remember the names off the top of my head.

You can either check the firms you've mentioned, or go to CampingFrance www.campingfrance.com/uk and use the "Search by criteria" box to search by region (for the west coast, choose Brittany, Loire Atlantique and/or New Aquitaine) and then by facilities and even size of campsite.

We are in SE and only 1.5 from Calais. We booked an early train, would leave the house at 4.30am and be in our mobile home for 5/6pm. Ours was very near La Palmyre as mentioned above, in a very French town called Ronce les Bains.

When you say north, how far north are you, and how far south do you want go? Where we had our van was mid way down. South I would have broken the journey and coming from the north to where we were I would either go to Calais and get a cheap travelodge or take the longer ferry crossing to Caen or Cherbourg, get a cabin and get some sleep. Pricey though.

As PP said, there are certain days you do NOT want to be travelling in France.

Le Grande Depart - 1st Sunday in August
Middle Saturday in August
Le Grande Retour - last Sunday in August

Pay for the Paege, you can get a tag to avoid having to stop and physically pay the tolls.

I don't believe you're thinking too much. I always do lots of research before choosing a holiday. It's part of the fun, and gives you a better chance of spending your precious time off and your hard-earned cash on something everyone will enjoy.

Look at the option of flights from Bristol, which is not too far for you I think.

As well as taking stuff, we found that you needed a car to get to the activities outside the campsite. A hire car for a fortnight, on top of four return air tickets, was just as expensive as the hotel, ferry and diesel, if not more so.

If you’re still considering flying, we flew to Bordeaux and hired a car. Nice easy drive to La Rive. We’re in Scotland and can’t face the long drive 😆It’s a great site, would highly recommend it. Enjoy your research and your holiday!

We are London based and would always choose to drive except for trips at Feb half term. Usually leave on a Friday morning, via the tunnel and stop for dinner and a pre-booked overnight hotel just off the autoroute. Good breakfast and set off the next day and arrive dinner time the next day. The worst part of the journey is always the bit in the U.K.! French roads are superb, there are good aires de service with decent food at regular intervals, the countryside is varied and the kids watch movies. It takes a bit longer but we find it less stressful than flying (we always check bags as a family and have had various mishaps). It is also much cheaper even allowing for crossing, fuel and péage fees. I also prefer driving my own car. We headed down middle Saturday last year, we were going to the mountains so I guess the coast would have been busier but traffic wasn’t too bad at all, a little bit around Lyon from what I recall.