The reason DR works is because at typical piston GA speeds, and typical winds in which UK PPL-level GA flies, the correction isn't very much. If you correct by say 10 degrees, and it should be 13, and your legs are say 10 miles long, the resulting lateral error in the ground position is tiny.
In a 60kt aircraft and with a 50kt wind aloft, the situation is much much worse. You can easily be looking at wind corrections of 45+ degrees. But there aren't many 60kt planes, very few people fly when the 2000ft wind is 60kt (that's 30-40kt on the ground), and almost nobody with a 60kt plane will be trying to fly it with that sort of wind on the ground.
So............ one gets away with it, due to the arithmetic of small angles.
All the rules of thumb mentioned will work just fine. Some are easier to work out than others, that's all.
The RAF gets away with it even better because the wind correction at 500kt when flying at relatively low levels is miniscule.
I have no chip on my shoulder, by the way. I just refuse to believe someone telling me, no matter how experinced they are, that I can fly a heading of 11.7 degrees versus 10 degrees. I've got 550 hours, do 150 hours a year, and while I make no claims for being able to fly I do happen to know that represents a reasonable currency in this business.
I have a £30,000 autopilot and even that could not hold a heading to that accuracy. I can probably just about read the HSI to that accuracy, without a magnifying glass. The only way to hold a heading within say 2 degrees is by following a GPS track, or by tracking a succession of navaids.