Do you know what they screw into behind the boards? I would expect timber battens, but we can’t be sure. Could also be metal studs of some sort.
There don’t really seem to be a lot of screws… what do others think?
You probably have a “mixed pressure system” at your kitchen tap, i.e. hot is low pressure, cold is direct from the mains. (Right?)
Taps do exist for that and do work. I think there are two channels all the way to the spout, so there is no mixing in the body of the tap.
I’ve tried to do this in my flat and found it essentially impossible. The boards were fixed with large ring-shank nails that need a lot of force to extract. They were driven in through the grooves, nearer to horizontal than vertical - so prizing up the edge of the board does not pull the nail in...
I have the Evolution one that is currently £60 at Screfix. It’s fine. Very sturdy (heavy); quick to put up (I mainly use it in the garden). The support arms are a bit… imprecise?
Please let us know what you end up using. There seem to be a range of products out there. 100 Mbit ethernet over *two* coax cables, without power, should be very easy for a modest range.