Well, it's Monday today, so most of France is shut. Offices are open, however, and I did manage to contact the water board about connecting me to the mains. The lady was polite but said that a wait of 3 to 4 weeks, between the man measuring up and the quote for the work arriving, was perfectly normal, and to wait another week or so for it to arrive before ringing again. The trouble is that after it arrives, it may be a long time before the work is actually done, and I can't have the Fosse Septique installed unless it can be filled with water when it is placed in the ground. Otherwise, apparently, if there is a heavy fall of rain, the soil replaced over the tank is not sufficient to hold it down when the rain percolates through the loosely-packed soil, can't get through the clay underneath, forms a lake and the concrete Fosse pops to the top like a skeleton rising to the surface in a horror movie.
The fosse was due to be installed in June, but maybe now that will be later...
Meanwhile the weather has been wet and warm - often VERY warm, which is what plants like! Consequently my 'lawn' is actually a wild flower meadow now. It's actually very pretty, though I need to cut some paths through it, as there is a danger of snakes if you walk in it.