Peugeot Speedometer

I'm sorry, Eitel, but I'm not clear as to what you wish to achieve.

If you want an supplementary speedo which is accurate and which can be easily read in big font (unlike the Peugeot speedo which is often illegible under that dashboard cowl) then use an old smartphone to which you've downloaded a GPS Speedo app - there are many free apps, and you do not need a SIM in the phone as it uses GPS. Or use a satnav, which likewise displays GPS speed. Both can run on their own batteries, or plugged into the 12v socket on the dash.

But you may be posing a different question? If so, can you elaborate, please?

Cymro

I always use an old iphone which has a free speedo app. Its battery will usually last long enough for a day's long journey. I bought a suction mount on a flexible arm, which I have permenantly stuck to the driver's quarter-light. Putting it in the bottom front corner of that pane means that it's possible to close the Remis blind all the way except for an inch or so at that corner. The phone speedo has large clear font, and is so much easier to read. It's accurate, and has other functions but I don't use them. 

A few years ago there was a thread on this Forum about this. If you can find it, it may offer other suggestions. 

Cymro