This really is the seasonal cookbook to his River Cottage Cookbook which was as much about self sufficiency as cookery.
I've enjoyed HF-W's books and TV series right from his very beginnings, but this is written from a position very few us will be in.
I'd love to eat only seasonal produce, the best organic and ethically raised livestock etc.
If I lived in Dorset I could obviously because it's reasonably readily available.
I live in the Thames Valley which does have such producers, they are 20 to 30 miles away by car, and impossible to reach by public transport unless you are prepared to spend most of the day travelling.
As for fish, my choice is supermarket a, b, or c, all selling fish I wouldn't touch.
So yes, living in the right area, with reasonable access, you can do it.
I could go skiing, but there are no mountains or snow near me !