The QXC is a VFR navigation exercise. If you can't do it safely you shouldn't pass your PPL; simple as that
Completely agree. However, navigation (and I speak as a Professional navigator, albeit marine) is (or should be) about the best use of all available information to verify position, course & track. That information should include all systems in the aircraft capable of providing information, such as GPS, radio nav aids etc. The theory that PPL nav training should be limited to compass stopwatch & chart nav only is IMHO, flawed.
PS IS it mandated anywhere that the QXC has to be navigated by DR?