To me, this is important and seems to be getting missed. I found it as I was researching NPF4 13 to reduce car parking obligations for an in-town development (design for pedestrian, cycling to be supported, 20-min neighbourhoods).
NPF4 introduced a new requirement that huts "will" be supported with some obligations on the part of the hutter (following the Good Practice being the main requirement).
This is a huge leap over "to be encouraged" or whatever get-out the councils had for 10 years.
When a Hut application is refused, Appeal. Cite NPF4 30 (d). State clearly that your hut is compatible with the surrounding area, in nature and scale. Attach the Good Practice Guidance. The Gov has given you the words to put, precisely in any Appeal. Add no superfuous bumf about your hut being for yoga or feeding squirrels: give them no room to wriggle. Just the facts. NPF4 30 (d).