Pelamid may know round that way better than me but I would also agree with the above ...google maps can be handy as well. Your unlikly to run into crowds.
There is quite alot of Cat1 fishing round that way, basically Trout/game so do check before you fish as they can be a bit picky about what you can and can't use.
A bit late replying to this, but it is in my 'patch'.
The Charente in that area is well beyond the Catagory 1 zone. In fact the Charente is Cat 2 all the way down from its source. Bizzarly though the Fisheries Dept release trout in the river in spring right down to Savigne and there are some Cat 1 rivers that confluence the Charente including the mini chalkstreams known as the Touvre and the smaller Son-Sonette that enter the Charente a lot further downstream at Gond-Pontouvre and near Mansle respectively .
Where the op was looking is chub and barbel water where the river meanders lazily through pasture land and splits and reforms creating narrow channels and islands. There is limited access and a 4x4 won't give much benefit down there as the river runs through enclosed farm land with few tracks allowing access. There are specific parcours de peche at Charroux and Savigne, but these aren't particularly good places. In August you will struggle to find a good stretch that isn't full of picnicers and bathers. The best place is downstream of Mansle near St Groux, but in August that will be full of carpistes as it is an area where night fishing is allowed.
To find the best places I use Google Earth initially, but I have the advantage that my work allows me to reccy the likely places and sort the wheat from the chaff before setting off to fish it. Holiday makers don't have that luxury.
