We met our old plumber in the DIY shop today, which reminds me of a song. The first thing he told us, with obvious enthusiasm, is that he will be retiring in a month, after all these years of work. He suggested to his employer that he might like to go part-time, but apparently that's difficult, so he's looking at going independent (as an auto-entrepreneur, the nearest thing France has to self-employment). He did really good work on our gîte installation so I told him that he should drop round with his business card if he takes the plunge. He said that I didn't need to tell him that, since he knows where all the installations are....
For the new kitchen I chose to use high-density polythene water pipe, known as PER over here. The pipes are cheaper than copper, but the fittings are more expensive. You can use a variety of types of fittings, and I chose to use the ones our friendly plumber used in the gîte; ones that you fix using slip-rings.
To affix a slip-ring fitting, you first slide the ring onto the PER pipe, then stretch the diameter of the pipe so that you can slide the fitting into it, then use a special tool to force the slip-ring back over the pipe and onto the fitting. You would not believe the number of times I forgot to slide the ring on first, only to discover that it will no longer go over the now-stretched pipe. The only solution is to cut the pipe and start again. I have not yet managed to get any of these fittings apart once put together, and they seem (touch wood) to be reliably watertight.
The blue box contains the kit of tools you need.The thing on the left with its handle in the air is the tool for stretching the pipe (you can see that it can cope with several different diameters of pipe). The red thing is the pipe cutter and the rest of it is the tool and attachments for forcing the ring back onto the fitting.
This picture shows that part of the plumbing installation that will go under the kitchen sink. It's reasonably compact and seems to be leak-proof. For best rigidity you need copper, but I think PER will be fine for me. (The blue pipe going off to the left is feeding water into the old kitchen for the time being.)