I think (happy to be corrected) that this is a newish campsite that has evolved out of parking bleu over the last few years so the map may be out of date.
You're correct. There was a discussion earlier about this.
The 'Camping Bleu' you see on the maps is Bleu Sud - Bleu Nord is just across the back lane running to Arnage and, as Piglet says, has evolved from unauthorised camping in the Bleu parking area. As far as I know, the facilities are the same as anywhere else - clean toilets, not enough showers and a stand pipe or three.
I'd accept it if I were you - if you later get the offer of KN, you can decide which ones to have.
Wimmille is right at the top of the pit straight, the first one on the northern end. Not directly opposite the pits, but a good view down the pit straight with the cars coming towards you, and part way round the Dunlop curve - well it used to be - it is right opposite a great big pile of sand/earth at the moment, so who knows what it will be like in June - and that goes for the rest of the circuit as well.
Del