Unfortunately, evil UK authorities used the BSE crisis which hit lots of grainfed cattle-herds to force ALL cattle, even 100% grassfed cattle, to be slaughtered at 30 months before they can gain a decent amount of raw fat.
All that said, I have done very well in raw wild game, minus the fatty raw organs, so, maybe, the issue of raw fat is not the end of the world as long as one is NOT doing RZC.
This is a big part of a big problem that often goes unnoticed in Low carb circles.
The practice of slaughtering at thirty months is the end of the world for those who rely on the fat and flesh of those animals as primary sustenance. The fact is that 30 month animals are not fully grown, and their tissues may not be as fortified with the accumulative nutrients and minerals as fully grown mature animals in their prime. So people who are attempting VLC while getting the majority of their calories from a limited selection of parts from immature animals will not be able to obtain optimal nutrition.
Traditional hunters would often go for the older fatter males, that lived without boarders and could forage for whatever it needed...... now most people have to chose parts and pieces from thirty month old adolescent animals that have been castrated and confined to limited pasture range with often limited variety of forage.
As for Burger, I think that his basic guidelines for honing ones instinct are a good staring point, but could be greatly expanded when it comes to seeking out the sources of ones nutrients. There is great value in going directly to the source, and paying close attention to the plants and animals you will be using for food while they are alive and in their natural environment. Over long periods of time observing the differences in quality within a wide variety of potential food sources one may begin to develop the kind of wisdom of discernment which guided our paleo ancestors in their own food choices.
No amount of dietary advise from strangers on the internet could possibly replace the kind of experience that one can get from foraging for ones own food, or killing your own animals while using ones own god given senses..... tasting the blood and inspecting the tissues before deciding if its good enough to eat it..... then if it is good, as the apex predator, one could chose to take only the best parts and leave the rest for the scavengers... like the grizzly bears who when fattening for winter will discard much of the lean meat of the fish they catch.