I don't think the Beckhams run a campsite in the South of France!!! Now seriously what do you mean by posh toilets? Over the years I have stayed at 6 different campsites in the South of France and have to say the quality of the toilet facilities do vary but most have been perfectly fit if not luxurious. I have heard of a couple of sites that do have individual private facilities but not sure where thry are.
We've stayed at quite a few campsites in France and the showers have always been individual with doors on, likewise the toilets. They are usually in a block not individual facilities for each pitch. They are sometimes unisex, but not showering communally and in your own cubicle with the door shut what matters who is next door!
We stayed here: http://www.ukcampsite.co.uk/sites/reviews.asp?revid=5427 where there are loos & showers for each row of pitches (14 as I recall). They were pretty nice and at least 2 rows had bigger blocks that were very modern. We have particular reasons why we have to be within hailing distance of a clean loo and they were fine for us. The rest of the site was pretty spiffing too, read my review:-)