Ben had quite an epic planning battle which is covered in his book. He argues that those working seasonally in a coppice need shelter, used to always be allowed a structure made from simple natural materials and that it was an accepted sustainable part of woodland management. It was advocating the same philosophy that enabled him to build where he is in Prickly wood.
Times have changed and few of us will work as much in our woods as Ben. Its an interesting debate as to what the 'need' is for woodland buildings beyond housing equipment. If the loophole in the regs is abused and hundreds of us start putting up what are essentially modest holiday homes in the woods, with kitchens, beds, etc. then the planners are likely to crack down or look to get regs tightened. I intend to put up a modest fairly empty shed and use it during the day as far as possible in the spirit of the regs, storing some low value woodland related bulky items there, use it as a bolt hole during showers. Its a delicate balance between enjoying being in the woods and overstepping the spirit of the planning guideline.
Just to add I had a bit of a chat with Ben Laws who had time to offer coppicing advice and comment on some pictures I sent him. Strikes me as a decent bloke, I'm pleased he's achieved his objectives.