The Navi in the boot had started acting up some time ago with the CD being ejected and reinserted in an endless loop. As I don't really use the outdated maps and system, I just removed the CD and stored it in the glove box with the possibility of having inadvertently f@cKed the Navi at some point, looming in the back of my mind.
Having nothing better to do today, I decided to have a look at the disc which sure enough was badly scratched from who knows how many years in there...
So I took it home and read it on the PC (the whole 16 Mb of data ). Tried to copy and label it by the windows explorer but the resulting copy did not work. So I had it copied again with Nero and it worked a treat. No more self-ejecting the disc and it loads pretty fast, too.
So before condemning your old CD based Navi, try a freshly copied CD on it.
Maps on mine are a decade+ old but still good enough for Athens. As useless a knowledge, I might actually try to learn the ancient thing. With so much ancient history in Athens, it won't be out of place...