Small update; The One X came back with a new shell but same screen and internals. The repair centre apparently did a factory reset and other worthless activities on-top of that. Nothing was fixed, of course.
So it is right back with Saturn, for another 2 week attempt to solve the actual listed problems.
In the meantime I did a side by side test with a friends One X and as I thought, his works as mine did when I first had it. The problems seem to be very much on the main-board, radios, who knows. Everything else is identical.
HTC hire other companies to do repairs in Germany as do many others, unfortunately my experience is that many repair centres here are bloody worthless.