After some digging I found H. Kerensky web site (thank Hans) the HOW-TO do this camera so I took it and started to work on her. Everything went ok, the original grease was solidified (and green) so it took me a while to clean it, but new bellows were needed, I asked around and it was 50₤ no less... I tried to do them myself but it ended more similar to a potato than any other known thing.
So I started digging again and I found that the Kershaw folding cameras share the same body, montage and measures than Agfa's Isolletes, even the 4 screws to take out the rear plate/holder (something not possible on Ikontas, Japanese cameras or Voigtlanders) so bellows can be installed as they should. I found one with a fungy lens, easy auction, for a 1/4 of the price of asking for new bellows, the seller checked the bellows before anything and he checked right!!
Now the Isolette III has leather bellows and my Nettar 518/16 the case I was looking for her

Here its the camera finished. And now the results from the test roll, some at the kids playground, focusing purposes and parallax errors (my bad, I can't remember)



Detail of the tools in case of fire.

Some flowers.



Heading to the lab, this pic was taking 1/10 at 4.5, without tripod.

So now I have a competitor at home for the Perkeo II and the Nettar 518/16, the advantage of the Isolette III is that it has rangefinder incorporated (non-coupled).
Thank you for watching.