Never had to chase the ‘aural null’ stuff but on one occasion I started one of those DME homing debacles.
I often wondered about the practicality of these requirements. While I am sure very few pilots ever had to do a an IMC DME Homing or an IMC aural null let down for real, these instrument let downs were well explained in the manuals issued to flight crew at the time. You could bitch all you like about the remote chances of ever having to fly these in your career. But it gave you confidence that if one of these events ever happened you had a fighting chance of survival.
It should be remembered that in those days hand flying on instruments was accepted as normal. Auto pilots were not that reliable and gyroscopic instruments could easily topple beyond certain angles of bank - usually over 55 degrees. Keep in mind during wartime a dog fight would always cause an AH and DG to topple often in IMC. The pilot didn't have the luxury of holding straight and level unaccelerated flight while he caged then uncaged his AH and DG all the while with a Messerschmitt up his arse.
Skill at limited panel flying today is vital as a fall back in case an AH fails in cloud. Most flying schools have quite good desk top flight simulators at moderate cost for students and pilots to practice with. Unfortunately many pilots cannot be bothered - mainly because loss of face (not only an Asian characteristic I might add) when they finish up in an unusual attitude while trying to fly straight and level on primary panel.