This is my favourite campsite in the world, depends how you feel about camping though! They also have self-catering cottages. We haven't been since having DS, mind -- it's got a great adventure playground but I'm not too sure what you'd do if it rains...
Just had a look and lovely as it looks I don't think it will suit as you can't book. I don't fancy going all that way and not having a guaranteed booking. I couldn't find any reference to self catering cottages. Is that something you have to phone about?
Think positive people! - Had many a drive over 24 hrs to Italy with small ones, with no problems -- its all about how you approach it with them -and your timings.. However, they will certainly pick up on your uncertain vibes if you're not up for it.
I'd be interested in your tips daffodil, we had a 2 1/2 hour car journey recently which was a nightmare. My DD escapes her car seat and just hates being in it. I had even bought a car DVD player hoping she may be entertained by that and it lasted about 25mins!
GN - no experience of car seat escapees - but rules is rules! For us we always started drives to Italy in the early evening - a short while before they were due to sleep. For us its approx 4 hours to dover. Then the excitement of tunnel/ferry etc. Out at the other end - its dark and so more sleep - and in another 8 hours we were almost three quarters of the way there and they'd slept most of it. Song and story tapes - hard work for the non driver for 2 hours ish and then a stop for breakfast. Some of the Swiss/Italian service stations have playgrounds which are great.
Final leg - loads of encouragement - lots of food - apple slices, carrot sticks, brioche etc - not too messy ( don't want to stop too often). More story tapes - I think we can all practically recite Ballet Shoes! Bit of I spy - as they get older - singing - 'reach for the sky!!' etc etc
When really concerned prior the trip I have resorted to 'gift bags' - a couple of cheap but entertaining prezzies, wrapped in several layers etc, which are firstly promised for good behaviour and then handed out and hopefully distract for at least...10 mins! Good luck!