Highspeed, virtually all NDB approaches in (Western?) Europe are designed with a 3 degree descent path in mind.
If the weather is just above NDB minima, with the NDB MDA being less than 500' AGL in many cases, would you fly straight and level in search of the airport?
What would the purpose of the "being established at 500 feet" SOP be? You're leveling off at say 475' AGL, adding thrust, then when you spot the runway after a mile of level flight, you cut the power again and pitch the nose down?
If the weather's so bad that it's even doubtful you'll see the runway at MDA, and an NDB approach is the only thing available, it might not be a good idea to go there in the first place.
Iz